Reflection liquid crystal display, method for producing the same, and method for driving the same

ABSTRACT

A reflection liquid crystal display is such that a transparent substrate is opposed to the first substrate with a liquid crystal layer placed therebetween, and the transparent substrate is disposed forward to the first substrate in the light-incident direction. A quarter-wavelength plate is disposed in the transparent substrate, and a polarization plate is disposed on the surface at the forward side thereof in the light-incident direction. And, a reflection layer besides acting as a color filter consisting of a cholesteric liquid crystal is disposed inside liquid crystal cells of the first substrate. In the case of a wide field-of-view angle, a scattering film is disposed forward to the polarization plate in the light-incident direction.

BACKGROUND OF THE INVENTION

[0001] 1. Technical Field of the Invention

[0002] The present invention relates to a reflection liquid crystaldisplay such as a display for a mobile terminal device, a terminaldisplay for utilizing various types of media for individuals, a displayof a mobile telephone, and a display in an amusement device such as agame machine, a method for producing the same, and a method for drivingthe same. More specifically, this invention relates to a reflectionliquid crystal display having excellent field-of-view anglecharacteristics, the production process of which is facilitated, amethod for producing the same and a method for driving the same.

[0003] 2. Description of the Related Art

[0004] Recently, demand for a reflection liquid crystal display, powerconsumption of which is reduced, has increased in line with developmentand diversification of mobile devices. Such a display that enables colordisplay has been increasingly desired for use in, particularly, mobiletelephone sets, mobile terminals, and office automation devices. Abrighter display is further required in view of mobility, and reasonablywide field-of-view angle characteristics are required. Especiallypreferable, since narrow field-of-view angle characteristics are desiredin an individual use although wide field-of-view angle characteristicsare desired where a plurality of people observes a display, a reflectionliquid crystal display that enables a changeover between a widefield-of-view angle and a narrow field-of-view angle is desired.

[0005] Conventionally, such types are widely used in reflection liquidcrystal displays, in which a polarization plate is used as in asupertwisted nematic type (STN type) or twisted nematic type (TN type)that has been widely used in transmission type liquid crystal displays.In the case of reflection type, only a single polarization plate isused, differing from the transmission type. However, since it isnecessary to switch reflection light, such a type is common, which is aso called single polarization plate used along with a quarter-wavelengthplate as described in, for example, T. Sonehara et al., Japan Display1989, Page 192 (1989).

[0006] A description is given of a display principle of a singlepolarization plate type, taking a normally white type, which has beenmost widely used, as an example (Prior art example 1). FIG. 1A and FIG.1B are views showing the display principle of a reflection type liquidcrystal element of a prior art single polarization plate type, whereinFIG. 1A shows an example in the case of white display, and FIG. 1B showsan example in the case of black display. Also, FIG. 1A and FIG. 1B showonly optical elements of the reflection liquid crystal display.

[0007] As shown in FIG. 1A, incident non-polarized light 1107 is broughtinto collision with a reflection plate 1104 after having passed througha quarter-wavelength plate 1102 of a wide-band and passed through aliquid crystal layer 1103 and returns in its inverted optical route,and, when the light passes through the polarization plate 1101, itenters eyes of people, wherein the light can be recognized as an image.At this time, by changing the state of polarization by utilizingelectro-optical effects of liquid crystal, switching of the reflectionlight can be carried out. First, the incident non-polarized light 1107enters the polarization plate 1101 and is converted to lightpolarization having a specified vibration direction. At this time, thepolarization plate is set so that the outgoing light becomes P-polarizedlight 1105. And, if the optical axis of the quarter-wavelength plate1102 is disposed so that it forms 45 degrees with respect to thetransmission axis of the polarization plate, the light that has passedthrough the quarter-wavelength plate 1102 becomes rightwardcircular-polarized light 1106 and enters the liquid crystal layer 1103.In either the TN mode or the STN mode, retardation of the liquid crystal1103 is set so that it gives λ/4, that is, a phase difference π/2 whenno voltage is applied. Therefore, light that has passed through theliquid crystal layer 1103 again becomes P-polarized light 1105 andreaches the reflection plate 1104. In the reflection, since theP-polarized light 1105 is reflected as it is P-polarized light 1105, itreturns in a completely inverted optical path of the path along which itentered, and is converted to rightward circular-polarized light 1106 bythe liquid crystal layer 1103. Further, the light becomes P-polarizedlight 1105 by the quarter-wavelength plate 1102 and is caused to radiatefrom the polarization plate 1101 as it is P-polarized light 1105. Thatis, white display is enabled in a state where no voltage is applied ontothe liquid crystal.

[0008] As shown in FIG. 1B, if voltage is applied to the liquid crystallayer 1103 and liquid crystal is erected so that the liquid crystalmolecules become perpendicular with respect to its substrate, theretardation of the liquid crystal layer 1103 becomes almost zero, and aphase difference 0 is given. That is, the liquid crystal layer 1103 doesnot give any influence to the state of polarization. In this state,where incident non-polarized light 1107 enters the polarization plate1101, light that has passed through the polarization plate 1101 andquarter-wavelength plate 1102 becomes rightward circular-polarized light1106 as described above. Herein, sine voltage is applied onto the liquidcrystal layer 1103, the liquid crystal layer 1103 does not change thestate of polarization, and the rightward circular-polarized light 1106passes through the liquid crystal layer 1103 as it is the rightwardcircular-polarized light 1106 and enters the reflection plate 1104.Since the advancement direction of the light is inverted by reflection,the rightward circular-polarized light 1106 becomes a leftwardcircular-polarized light 1108 and returns. Since the liquid crystallayer 1103 also does not change the state of polarization, light thatpassed through the liquid crystal layer 1103 enters thequarter-wavelength plate 1102 as it is a leftward circular-polarizedlight, and it becomes S polarization 1109 whose direction ofpolarization is different by 90 degrees from the P-polarized light 1105,wherein the light enters the polarization plate 1101. Since thetransmission axis of the polarization plate 1101 is set so that it canmake the P-polarized light pass therethrough, wherein the S polarization1109 cannot pass through the polarization plate 1101, and it isdisplayed as black. Depending upon the intensity of application voltage,the retardation of the liquid crystal layer 1103 can be varied, whereinintermediate colors can be displayed.

[0009] Also, Japanese Unexamined Patent Application No. Hei-10-20323(hereinafter called a “prior art example 2”) has disclosed a liquidcrystal display whose production is facilitated and field-of-view anglecharacteristics are excellent. In the prior art example 2, a liquidcrystal layer in which two or more types of slight areas coexist isplaced between two substrates, and has an electrode having an openingformed on at least one substrate, and a second electrode (controlelectrode) secured in the opening, wherein a voltage that is higher thanthe voltage applied between the electrode having the opening and theelectrode opposed thereto is applied between the control electrode andthe electrode opposed thereto, thereby securing a wide field-of-viewangle.

[0010] Further, Japanese Unexamined Patent Publication No. Hei-7-239471(hereinafter called a “prior art example 3”) discloses the use of acholesteric material layer and phase plate, that act as a reflectionlayer, for the purpose of improving the brightness and color purity of areflection liquid crystal display. In the prior art example 3, the upperand lower substrates are disposed so as to be opposed to each other, aliquid crystal layer is placed and secured between these two substrates,and the prior art example 3 comprises a phase plate disposed on theopposite side of the upper substrate liquid crystal layer, an upperpolarization plate disposed further thereon, a cholesteric materiallayer that is disposed on the surface of the lower substrate opposed tothe upper substrate and is disposed between the surface and the liquidcrystal layer, and an optical absorption layer formed at the oppositeside of the lower substrate liquid crystal layer. Thus, the cholestericmaterial layer is formed in liquid crystal cells and is used as a colorfilter, whereby shadows in the dark display portion can be removed.

[0011] In addition, a liquid crystal display in which a widefield-of-view angle and a narrow field-of-view angle are changed over isdisclosed in Japanese Unexamined Patent Application Nos. Hei-6-59287 andHei-10-197844 (hereinafter respectively called a “prior art example 4”and a “prior art example 5”).

[0012] In the prior art example 4, the field-of-view angle oftransmission liquid crystal cells is changed over by adjusting theoutgoing light, utilizing a guest-host liquid crystal or grating. Also,in the prior art example 5, such a method is disclosed, in which thereflection type and transmission type are changed over by utilizingtransmission and dispersion of macromolecular dispersion liquid crystal,and the changeover of the field-of-view angle of a liquid crystaldisplay is carried out by utilizing the guest-host liquid crystal.

[0013] However, in the case of displaying by means of the mode of priorart example 1, as has been made clear in FIG. 1A, since the light thatenters the liquid crystal layer 1103 in bright display is based onlinear polarization, in the TN mode or STN mode, it is necessary to setthe rubbing direction and polarization direction, so that they are madecoincident with each other or different by 90 degrees from each other,in order to obtain a high transmittivity, and it is necessary toaccurately control the rubbing direction and arrangement of thepolarization plate 1101 and a wide-band quarter-wavelength plate 1102.In addition, if a perpendicular orientation mode and amorphous TN mode,which can shorten the production process without requiring any rubbing,are used, a dark display portion is securely produced in a brightdisplay state, wherein sufficient brightness cannot be obtained.Further, another problem occurs in that, since the field-of-view angleis unitarily determined by design of a reflection plate, the widefield-of-view angle and narrow field-of-view angle cannot be changedover.

[0014] Still further, in the art described in the prior art example 2,such problem occurs in that a voltage must be applied to the secondelectrode in order to control its drive and a wide field-of-view angleand narrow field-of-view angle cannot be switched.

[0015] In addition, in the art described in the prior art example 3, inthe phase plate, no consideration is taken with respect to therelationship between the direction of liquid crystal orientation and thedirection of polarization of reflection light that enters the liquidcrystal layer in the TN and STN modes, and no device is provided so thatbrightness can be secured in regard to fluctuations of a process such asa rubbing direction, etc. In particular, even if a perpendicularorientation mode or amorphous TN mode, which can shorten the productionprocess not requiring any rubbing, is used, no consideration is providedwith respect to a method and/or construction of securing sufficientbrightness. Therefore, sufficient brightness cannot be secured by such asimple process. Also, where the cholesteric material layer is used as areflection layer, since the range of field-of-view angle that is capableof observing selection reflection is narrow, it is necessary to furtherwiden the field-of-view angle in practice. However, a problem occurs inthat a wide field-of-view angle and a narrow field-of-view angle cannotbe changed over.

[0016] Still further, in the prior art example 4, it is disclosed onlythat the outgoing light is adjusted by utilizing a guest-host liquidcrystal or grating in order to adjust the field-of-view angle oftransmission liquid crystal cells. No disclosure is provided withrespect to a reflection type. Furthermore, where the field-of-view angleis changed over by the system disclosed in the prior art example 4, aproblem occurs in that, although it is possible to only narrow and/orlimit, in a certain area, the field-of-view angle of liquid crystalcells to be used, it is not possible to widen the field-of-view angle ofthe liquid crystal cells.

[0017] In addition, in the prior art example 5, as in the prior artexample 4, although it is possible to only narrow and/or limit, in acertain area, the field-of-view angle of liquid crystal cells to beused, it is not possible to widen the field-of-view angle of the liquidcrystal cells. Therefore, it is necessary to use a mode in which thefield-of-view angle of the liquid crystal cells is wide. A liquidcrystal mode having practical brightness and high contrast in thereflection type is only a single polarization plate type of TN as in theprior art example 1. However, another problem occurs in that thefield-of-view angle in the mode is narrow, and a practically sufficientfield-of-view angle cannot be obtained by the system by which thefield-of-view angle is further narrowed.

[0018] Therefore, as described above, it is difficult to securesufficient brightness by a single polarization plate type in which aconventional TN or STN mode is employed. Still further, it is necessaryto accurately control the rubbing direction, etc., and tolerance isnarrow with respect to fluctuations in the process. In particular, it isimpossible to secure sufficient brightness with respect to theperpendicular orientation not requiring any rubbing and the mode ofamorphous TN, etc. In addition, still another problem occurs in that thenecessary field-of-view angle in practice cannot be secured, and thefield-of-view angle cannot be changed over.

SUMMARY OF THE INVENTION

[0019] It is therefore an object of the invention to provide areflection liquid crystal display, having an excellent field-of-viewangle, which can display brightly with excellent color purity in a modeof perpendicularly-oriented liquid crystal and amorphous TN, etc., whichdoes not require any rubbing, and can be easily produced, and in which awide field-of-view angle and a narrow field-of-view angle can be simplychanged over, a method for producing the same, and a method for drivingthe same.

[0020] A reflection liquid crystal display according to the inventioncomprises: a first substrate; a second transparent substrate disposed atthe forward side in the incident direction of light so that it isopposed to the first substrate; a liquid crystal layer secured andplaced between said first substrate and second substrate; a colorfiltering layer consisting of a cholesteric material layer providedbetween said first substrate and liquid crystal substrate; a lightabsorbing layer secured rearward of said color filtering layer in theincident direction of light at said first substrate side; aquarter-wavelength plate secured at the second substrate side; and apolarization plate disposed further forward of the incident direction oflight than the quarter-wavelength plate.

[0021] Another reflection liquid crystal display according to theinvention comprises: a first substrate; a second transparent substratedisposed forward of the incident direction of light so that it isopposed to the first substrate; a liquid crystal layer secured andplaced between said first substrate and second substrate; a colorfiltering layer consisting of a cholesteric material layer providedbetween said first substrate and second substrate; a light absorbinglayer secured rearward of said color filtering layer in the incidentdirection of light at said first substrate side; a three-colorcholesteric material layer, which is provided at the second substrateside and has an inverted twist of that of said cholesteric materiallayer.

[0022] In the present invention, light that enters the liquid crystallayer is subjected to circular polarization without fail, the intensityof light radiating from the liquid crystal layer is not influenced bythe direction of orientation of liquid crystal on the plane parallel tothe substrate surface. Therefore, a bright white display is enabledregardless of the direction and angle of the liquid crystal. As aresult, in the TN or STN mode, even if the rubbing direction slips inthe process of production, this does not influence the display at all.In addition, in modes not requiring any rubbing such as theperpendicular orientation mode or amorphous TN mode, blackening portionswill not be produced in the white display as in the prior arts.Therefore, a remarkably bright display is enabled in comparison with theprior arts. Further, it is enough that the liquid crystal layer has afunction by which retardation (dΔn), which is a product obtained bymultiplying the refractive index anisotropy Δn of liquid crystalmolecules by the thickness d of the liquid crystal layer, is changed byλ/2 (with a phase difference π). Therefore, even in a high-speed modeother than the abovementioned, this can be used without any necessity ofaccurate control in the rubbing direction.

[0023] Also, in the present invention, it is preferable that theinvention is provided with a scattering layer that scatters lightforward of the incident direction of light of said polarization plate orforward of the incident direction of light of said three-colorcholesteric material layer. Said scattering layer has two transparentelectrodes disposed so as to be opposed to each other and amacromolecular dispersion liquid crystal layer placed and securedbetween these transparent electrodes, and may be such a type that canchange over transmission and dispersion of said macromoleculardispersion type liquid crystal layer by applying voltage to saidmacromolecular dispersion liquid crystal layer. A wide field-of-viewangle and a narrow field-of-view angle can be changed over by attachingor detaching a scattering film or switching the macromoleculardispersion liquid crystal layer. In particular, in the presentinvention, since a color filtering layer consisting of a cholestericmaterial layer is provided at the side where the liquid crystal layer ofthe first substrate exists, a problem of so-called parallax does notoccur. In addition thereto, in the invention, since the color filteringlayer consisting of a cholesteric material layer is provided at the sidewhere the liquid crystal layer of the first substrate exists, and thedirection of selection reflection of the cholesteric material is limitedto a specified direction, only automatically collimated light isreflected on the scattering layer. Therefore, no problem in view ofparallax does occur, wherein it is possible to obtain a widefield-of-view angle. To secure a narrow field-of-view angle, suchadjustment may be carried out, by which the scattering is removed or theangle of dispersion is reduced. In the case where only a reflectionplate consisting of a cholesteric material layer is used, a narrowfield-of-view angle limited in only the direction of selectionreflection can be made into a wide field-of-view angle which issufficient in practice, by using a scattering film or a macromoleculardispersion liquid crystal layer.

[0024] Further, the invention may be provided with a plurality ofscanning signal lines secured on the surface of said first substrateopposed to said second substrate and a plurality of picture signal linesdisposed on these scanning signal lines in the form of a matrix, aplurality of thin-film transistors formed so as to correspond to theintersection of said scanning signal lines and said picture signallines, at least one pixel that is constituted by an area surrounded bysaid plurality of scanning signal lines and picture signal lines, pixelelectrodes that are connected to said thin-film transistor correspondingto respective pixels and are formed rearward of said liquid crystallayer in the incident direction of light, and a common electrode that isformed forward of said liquid crystal layer in the incident direction oflight and applies a reference voltage to said plurality of pixels.Thereby, since pixel electrodes are disposed between the color filteringlayer and liquid crystal layer, alignment between the color filteringlayer and pixel electrodes is no longer required, wherein theoverlapping accuracy of the first and second substrates can beremarkably relieved. Still further, since the pixel electrodes aredisposed between the color filtering layer and the liquid crystal layer,influence of an electric field in the lateral direction from thescanning signal electrodes and picture signal electrodes can beremarkably relieved.

[0025] In addition, in at least either one of said scanning signalelectrode or said picture signal electrode, a part of said pixelelectrodes or a shielding electrode may be disposed forward in theincident direction of light. Thus, in the case of an active matrixliquid crystal display, by disposing a shielding electrode above atleast either one of the scanning signal electrode or picture signalelectrode, no influence is received in the lateral direction from thescanning signal electrode and picture signal electrode.

[0026] Also, the above pixel electrodes may be circular or equilaterallypolygonal to have more sides than those of a triangle, and said commonelectrode has a larger area, when being observed from right above, thanthat of said common electrode, and is formed at a position where it cancover up the entirety of said pixel electrode. Further, said pixelelectrode is shaped so that a plurality of circles or equilateralpolygons which have more sides than those of a triangle range one afteranother while the common electrode may have a larger area, when beingobserved from right above, than that of said pixel electrode and isformed at a position where it covers up the entirety of said pixelelectrode. Still further, said common electrode may be formed on almostthe entire surface of said second substrate.

[0027] In addition, said pixel electrode is provided with cuts formed atequidistant positions on the circumference or at the corners of apolygon, or may be provided with projections protruding outward atequidistant positions on the circumference or at the corners of apolygon, or a recess may be formed at a part of said pixel electrode.

[0028] Thereby, it is possible to orient and divide liquid crystal cellsas necessary, in view of the field-of-view angle characteristics whenbeing used in a narrow field-of-view angle, uniformity of the brightnesson the panel surface, and response rate, etc. As described above, wherevoltage is applied between such electrodes, oblique electric fields areproduced up and down with symmetry well secured. For example, in liquidcrystal having a dielectric constant of negative anisotropy (dielectricanisotropy, which is perpendicularly oriented, the number of directionsalong which liquid crystal molecules fall down becomes two or more,wherein it becomes possible to smoothly orient and divide liquid crystalin pixels. That is, a boundary of division is produced at the center ofa pixel due to an oblique electric field that is naturally produced, andliquid crystal molecules are caused to fall down from the end of thepixel electrode toward the middle. If the shape of the pixel electrodeis made symmetrical, liquid crystal molecules are caused to naturallyfall down from respective sides of the pixel electrode toward the middlethereof. Therefore, they are naturally divided. Polygons are notnecessarily made equilateral, wherein some deformation may be permitted.

[0029] Further, said liquid crystal layer may include macromolecularorganic compounds.

[0030] Still further, in said liquid crystal layer, the anisotropy ofthe dielectric constant of liquid crystal is negative, when no voltageis applied, liquid crystal molecules may be oriented in a directionalong which the liquid crystal molecules are made orthogonal to saidfirst substrate and second substrate.

[0031] In this case, it is preferable that said liquid crystal layer isgiven a pre-tilt angle in advance in the direction along which theliquid crystal molecules fall down when voltage is applied.

[0032] Also, in said liquid crystal layer, the anisotropy of thedielectric constant of liquid crystal is positive, and it may be suchthat it has a twisted nematic structure when no voltage is applied, saidliquid crystal layer in the respective pixels may have two or more typesof minute areas in which the rise directions of liquid crystal moleculesdiffer from each other, or said liquid crystal layer in the respectivepixels may have two or more types of minute areas in which the twistingdirections of the liquid crystal molecules differs from each other, orsaid liquid crystal layer in the respective pixels may have four typesof minute areas in which the twisting direction and rise direction ofliquid crystal molecules differ from each other. In this case, it ispreferable that the pre-tilt angle of the liquid crystal molecules inthe boundary phase between said first substrate and second substrate is1 degree or less.

[0033] In this case, the pixel electrode is shaped so as to have goodsymmetry, the common electrode covers the entirety of the upper part ofthe pixel electrode when being observed from above, and is formed sothat its area becomes larger than that of the pixel electrode, wherein,when voltage is applied between the pixel electrode and the commonelectrode, an oblique electric field is produced in the liquid crystallayer with good symmetry secured due to the shape characteristics of theupper and lower electrodes. Although there is a possibility that bothrightward twist and leftward twist are generated in respective parts ofthe pixels, one of the twisting directions is preferentially produced inan area where respective pixels are divided, and the state oforientation is automatically produced, and in the case of twistednematic orientation, pixel division having good symmetry can benaturally secured. Also, a chiral agent may be provided in the liquidcrystal layer. In this case, two-divided TNs having only a differentrise direction are secured, wherein it becomes possible to orient anddivide liquid crystal in the pixels.

[0034] In addition, in said liquid crystal layer, the anisotropy of thedielectric constant of liquid crystal is positive, and the liquidcrystal layer has a homogeneous structure when no voltage is applied.Said liquid crystal layer of the respective pixels has two or more typesof minute areas in which the rise directions of the liquid crystalmolecules differ from each other. In this case, it is preferable thatthe pre-tilt angle of the liquid crystal molecules on the boundary phasebetween said first substrate and second substrate is 1 degree or less.

[0035] In this case, the pixel electrode is shaped so as to have goodsymmetry, and the common electrode covers the entirety of the upper partof the pixel electrode when being observed from above, and is formed sothat its area becomes larger than that of the pixel electrode. Ifvoltage is applied between the pixel electrode and the common electrode,an oblique electric field is produced with good symmetry secured. Sincethe direction orientation of liquid crystal is regulated on the boundaryphase between the substrates, two types of domains in which the risedirections differ from each other are produced. In the case ofhomogeneous orientation, it is preferable that a recess is provided atthe middle of the pixel electrode particularly in order to stabilize theboundary phase.

[0036] A method for producing a reflection liquid crystal displayaccording to the invention comprises the steps of: forming a thin filmtransistor on a first substrate; forming an optical absorption layer onsaid first substrate; forming a color filtering layer consisting of acholesteric material layer on said optical absorption layer; forming apixel electrode on said color filtering layer and connecting the same tosaid thin-film transistor; forming a common electrode on a secondsubstrate; making a pixel electrode of said first substrate and a commonelectrode of said second substrate be opposed to each other, and forminga liquid crystal layer including a macromolecular organic compoundbetween said first substrate and second substrate; forming aquarter-wavelength plate on said second substrate; and forming apolarization plate on said quarter-wavelength plate; wherein the processof forming said liquid crystal layer includes a process for pouringliquid crystal including monomer or oligomer between said firstsubstrate and second substrate, and a process of making said monomer andoligomer macromolecular in liquid crystal.

[0037] In the invention, by making polymerizable monomer or oligomer,which is mixed in liquid crystal at a slight ratio, the macromolecularorganic compound after the initial orientation is controlled by applyingvoltage between the common electrode and pixel electrode, whereby thebeginning liquid crystal orientation can be made further secure. Whencontrolling the initial orientation, the temperature may be loweredwhile applying voltage between the common electrode and pixel electrodeafter the liquid crystal layer is made isotropic by heating, or it issufficient that voltage may be applied between the common electrode andpixel electrode at room temperature. Also, a reaction of making themonomer macromolecular may be carried out before and during heating inan isotropic phase, and after cooling down. Where voltage is appliedbetween the common electrode and pixel electrode at room temperature andinitial orientation is controlled, the reaction may be caused to occurbefore or after voltage is applied. Thus, it is possible to orient anddivide liquid crystal in the form of normal drive.

[0038] A process of forming a pre-tilt angle in liquid crystal moleculesby light irradiation may be provided after the process of forming saidliquid crystal layer.

[0039] In addition, said light irradiation may be carried out by obliqueirradiation of light with respect to said first substrate and secondsubstrate, by oblique irradiation of polarized light with respect tosaid first substrate and second substrate, or by irradiation ofpolarized light from the perpendicular direction with respect to saidfirst substrate and second substrate. Thereby, the pre-tilt angle iscontrolled in advance on the substrates in compliance with a divisionshape by using a method of orienting light, etc., wherein the control ofthe initial orientation can be remarkably and securely carried out. And,an effect of an oblique electric field and an effect of the pre-tiltangle synergetically operate, wherein the division orientation can beremarkably more effectively carried out than in the case of only eitherof them.

[0040] A method for driving a reflection liquid crystal displayaccording to the invention is featured in that the display candot-invertedly drive in a reflection liquid crystal display described inany one of claims 1 through 25.

[0041] In the invention, there is no problem in normal cases if theinterval between pixels is sufficiently separated from each other asregards division. However, especially, in a case where pixels approacheach other due to limitations in design, a state of generation of anoblique electric field is made further preferable by carrying outso-called dot-inverted drive in which the polarities (positive andnegative) of the voltage applied onto respective pixels adjacent to eachother are inverted when driving the display, whereby more satisfactorydivision is enabled.

[0042] A method for driving another reflection liquid crystal displayaccording to the invention is featured in that a black state is enabledbefore one frame is finished, in a reflection liquid crystal displaydescribed in any one of claims 1 through 25, wherein separation or cutof moving pictures can be further improved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0043]FIG. 1A and FIG. 1B are views showing the display principle of aprior art reflection liquid crystal element of a single polarizationplate type, wherein

[0044]FIG. 1A is an exemplary view of a white display, and

[0045]FIG. 1B is an exemplary view of a black display;

[0046]FIG. 2A and FIG. 2B are views showing the principle of the presentinvention, wherein

[0047]FIG. 2A is an exemplary view showing an OFF (dark) state of areflection liquid crystal display, and

[0048]FIG. 2B is an exemplary view showing an ON (bright) state of thereflection liquid crystal display;

[0049]FIG. 3 is a sectional view showing a reflection liquid crystaldisplay according to a first embodiment of the invention;

[0050]FIG. 4 is an exemplary view showing the direction of atransmission axis of a quarter-wavelength plate and direction of opticalaxis of a polarization plate where incident light becomes rightwardcircular-polarized light;

[0051]FIG. 5 is a sectional view showing a reflection liquid crystaldisplay according to a second embodiment of the invention;

[0052]FIG. 6A and FIG. 6B are sectional views showing a reflectionliquid crystal display according to a third embodiment of the invention,wherein

[0053]FIG. 6A shows a state where no voltage is applied onto amacromolecular dispersion liquid crystal layer, and

[0054]FIG. 6B shows a state where voltage is applied onto amacromolecular dispersion liquid crystal layer;

[0055]FIG. 7 is a sectional view showing a liquid crystal elementaccording to a fourth embodiment of the invention;

[0056]FIG. 8 is a sectional view showing a reflection liquid crystaldisplay according to a fifth embodiment of the invention;

[0057]FIG. 9A is a plan view showing a reflection liquid crystal displayaccording to a sixth embodiment of the invention, and

[0058]FIG. 9A is a cross-sectional view taken along the line A-A in FIG.9A;

[0059]FIG. 10A through FIG. 10C are exemplary views showing the shape ofelectrodes that can be preferably used in a reflection liquid crystaldisplay according to the invention;

[0060]FIG. 11A and FIG. 11B are exemplary views showing the shape ofelectrodes that can be preferably used in a reflection liquid crystaldisplay of the invention;

[0061]FIG. 12A and FIG. 12B are exemplary views showing the shape ofelectrodes that can be preferably used in a reflection liquid crystaldisplay of the invention;

[0062]FIG. 13A is a plan view showing a reflection liquid crystaldisplay according to a seventh embodiment of the invention, and

[0063]FIG. 13B is a cross-sectional view taken along the line B-B inFIG. 13A;

[0064]FIG. 14A is a sectional view showing a reflection liquid crystaldisplay according to an eighth embodiment of the invention; and

[0065]FIG. 14B is a plan view showing a liquid crystal layer of thepresent embodiment;

[0066]FIG. 15A is a sectional view showing a reflection liquid crystaldisplay where the orientation direction of liquid crystal is regulated;and

[0067]FIG. 15B is a plan view showing a liquid crystal layer of areflection liquid crystal display shown in FIG. 15A; and

[0068]FIG. 16A is a sectional view showing a reflection liquid crystaldisplay having a pixel electrode in which a recess is formed, and

[0069]FIG. 16B is a plan view showing a liquid crystal layer of areflection liquid crystal display of FIG. 16A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0070] Hereinafter, a detailed description is given of preferredembodiments according to the invention. A reflection liquid crystaldisplay according to the present invention is featured in that a liquidcrystal layer is placed and secured between two substrates, a colorfiltering layer consisting of at least one cholesteric material layer isdisposed between the first substrate and second substrate, an opticalabsorption layer is disposed rearward of the color filtering layer inthe incident direction of light of the first substrate, a wide-bandquarter-wavelength plate is disposed at the second substrate side, andfurther a polarization plate is further forward in the incidentdirection of light than the quarter-wavelength plate. In this case,although the quarter-wavelength plate and polarization plate may bedisposed at any side of the second substrate, it is preferable that theyare installed for the sake of ease in production at the side where noliquid crystal of the second substrate exists, that is, outside theliquid crystal cells.

[0071] Also, if a three-prime-color cholesteric material layer having aninverted twist of the cholesteric material layer that is disposed in thefirst substrate is used instead of a combination of a wide-bandquarter-wavelength plate and a polarization plate, an effect can bebrought about, which is similar to the case where the combination ofsaid wide-band quarter-wavelength plate and polarization plate has beenused. The three-prime-color cholesteric material layer may be disposedat either of the surface at the forward side (outside the liquid crystalcell) in the incident direction of light of the second substrate or thesurface at the rearward side (inside the liquid crystal cell) in theincident direction of light of the second substrate.

[0072] Further preferably, a reflection liquid crystal display accordingto the invention is featured in having a scattering film on the surfaceat a further forward side in the incident direction of light than thepolarization plate or three-prime-color cholesteric material layer. Inorder to simply change a wide field-of-view angle to a narrowfield-of-view angle or vice versa, it is preferable that the scatteringfilm can be easily attached and detached. Also, in order to simplychange a wide field-of-view angle to a narrow field-of-view angle orvice versa, a scattering film may be constituted by a macromoleculardispersion liquid crystal layer, wherein a wide field-of-view angle anda narrow field-of-view angle may be changed over by turning ON and OFFthe voltage so that a scattered state (a wide field-of-view angle) iseffected with no voltage applied, and a transmitted state (a narrowfield-of-view angle) is effected with voltage applied.

[0073] In either case, it is important that the second substrate has awide-band quarter-wavelength plate and a polarization plate, and a colorfiltering layer consisting of a cholesteric material layer is providedat the side where the liquid crystal layer of the first substrateexists, that is, in the liquid crystal cell. At this time, thecholesteric material layer operates as a color filtering layer, wherebyit is possible to secure a bright display free from any parallax, whichcannot be obtained by any of the prior art methods.

[0074] Next, a description is given of the operation principle of aliquid crystal display according to the present invention that can bringabout said effects.

[0075] In the invention, in a case where a TN or STN mode is used, anormally black mode is brought about, in which an OFF (dark) state iseffected when voltage is 0, and an ON (bright) state is effected whenvoltage is applied. FIG. 2A and FIG. 2B are views that explain theprinciple of the invention, wherein FIG. 2A is an exemplary view showingan OFF (dark) state of a reflection liquid display, and FIG. 2B is anexemplary view showing an ON (bright) state of the reflection liquidcrystal display. Also, in the present embodiment, a description is givenof a case where a reflection plate and a quarter-wavelength plate aredisposed outside the liquid crystal cell. Incident light 1007 passesthrough a polarization plate 1001, a quarter-wavelength plate 1002, anda liquid crystal layer 1003 in order, and in a dark state, the lightpasses through a color filtering layer 1010 and is absorbed in anoptical absorbing body 1011. Also, in a bright state, the light isreflected by the color filtering layer 1010 and is caused to radiate inthe reverse route of the above.

[0076] When no voltage is applied to the liquid crystal layer 1003, asshown in FIG. 2A, non-polarized incident light 1007 enters thepolarization plate 1001 as in FIG. 1A and FIG. 1B and is converted topolarized light having a specified direction of oscillation. At thistime, the polarization plate 1001 is set so that the outgoing lightbecomes P-polarized light 1005. And, if the optical axis of thequarter-wavelength plate 1002 into which the P-polarized light 1005 isincident is disposed so that it forms 45 degrees with respect to thetransmission axis of the polarization plate, the light that passedthrough the quarter-wavelength plate 1002 becomes a rightwardcircular-polarized light 1006, and enters the liquid crystal layer 1003.In the invention, in both the TN mode and STN mode, retardation of theliquid crystal layer 1003 is set so that λ/2, that is, a phasedifference π is given when no voltage is applied. Therefore, the lightthat passed through the liquid crystal layer 1003 becomes a leftwardcircular-polarized light 1008 and reaches the reflection plate 1010consisting of a cholesteric liquid crystal. Herein, if therightward-twisted cholesteric material layer is used, the leftwardcircular-polarized light 1008 passes through the reflection layer 1010,and is absorbed by the optical absorption body 1011, wherein a blackdisplay is brought about.

[0077] Further, as in FIG. 1B, as shown in FIG. 2B, if voltage isapplied to the liquid crystal layer 1003 and liquid crystal moleculesare caused to be erect so that they become perpendicular with respect tothe substrate, the retardation of the liquid crystal layer 1003 becomesalmost zero, and a phase difference 0 is given. In this state, even ifthe rightward circular-polarized light 1006 enters the liquid crystallayer 1003, the liquid crystal layer 1003 does not influence a state ofpolarization, and the light that passed through the liquid crystal layer1003 reaches to the reflection layer 1010 consisting of cholestericliquid crystal as it is a rightward circular-polarized light 1006. Atthis time, by the reflection plate consisting of rightward-twistedcholesteric liquid crystal, the rightward circular-polarized light 1006is reflected and is returned after it is made into a rightwardcircular-polarized light 1006. Since the liquid crystal layer 1003 doesnot change the state of polarization, the rightward circular-polarizedlight 1006 passes through the quarter-wavelength plate 1002 and returnsto the P-polarized light, wherein it passes through the polarizationplate 1001 and radiates, wherein the white display is effected. As inthe prior arts, since it is possible to change the retardation of theliquid crystal by changing the intensity of application voltage, displayof intermediate colors can be brought about.

[0078] The point of the invention, which is remarkably different fromthe prior arts is in that light incident into the liquid crystal layer1003 is circular-polarized light without fail. That is, as shown in FIG.2B, since the light that is reflected by the reflection layer 1010 andis incident into the liquid crystal layer 1003 is circular-polarizedlight, the intensity of the light radiating from the liquid crystallayer 1003 is not influenced by the direction of orientation(hereinafter called an “azimuth direction”) of liquid crystal in a planein the direction parallel to the substrate surface. Therefore, theinvention can bring about an excellent effect, by which a brightly whitedisplay is enabled, regardless of the liquid crystal being oriented inany azimuth direction. Resultantly, in the TN or STN mode, an excellentadvantage can be brought about, by which even if the rubbing directionslips in the process of production, this does not influence at all.Still further, in a mode that does not require rubbing as in aperpendicularly oriented mode or amorphous TN mode, there is no casewhere a blackening portion is produced in a white display as in theprior arts. Therefore, a remarkably bright display is enabled incomparison with the prior arts, wherein there is a remarkably largeadvantage in that it is possible to produce a bright reflection liquidcrystal display by simplified processes. That is, since it is enoughthat the liquid crystal layer 1003 has a feature of varying theretardation by λ/2 (phase difference π) regardless of the orientation ofthe azimuth angle, in high speed modes other than the above, thereflection liquid crystal display can be used without requiring accuratecontrol of the rubbing direction.

[0079] Another advantage of the invention resides in that a scatteringfilm or macromolecular dispersion liquid crystal layer, etc., isdisposed instead of a scattering layer, and it is possible to easilychange over a wide field-of-view angle and a narrow field-of-view angleor vice versa by attaching or detaching the scattering film or switchingthe macromolecular dispersion liquid crystal layer. In particular, sincethe color filtering layer consisting of a cholesteric material layer isprovided at the side where the liquid crystal layer of the firstsubstrate exists, a so-called parallax problem does not occur. Inaddition to this feature, by provision of the scattering film ormacromolecular dispersion liquid crystal layer, it becomes easy tocontrol the field-of-view angle. Especially, in the case where anattempt is made to obtain a wide field-of-view angle by utilizing thelight scattering property of the scattering film or macromoleculardispersion liquid crystal layer, a problem of parallax occurs unlesslight that is incident into the film is not collimated well. However, inthe invention, since the color filtering layer consisting of acholesteric material layer is provided on the liquid crystal layer ofthe first substrate, and the direction of selection reflection of thecholesteric liquid crystal is limited to a specified direction, onlylight that is automatically collimated is permitted to be reflected onthe scattering layer. Therefore, the problem of parallax does not occur,and a wide field-of-view angle can be obtained. In the case where anattempt is made to obtain a narrow field-of-view angle, the scatteringproperty may be removed or the angle of the scattering may be adjustedso as to be decreased. Thus, in the case where only a reflection plateof a cholesteric material layer is used, which does not use anyscattering film, a narrow field-of-view angle that is limited to onlythe direction of selection reflection can be widened to a field-of-viewangle which is sufficient in practice, by using the scattering film or amacromolecular dispersion liquid crystal layer.

[0080] Also, since, in the liquid crystal layer of a reflection liquidcrystal display, a feature of widening the field-of-view angle isachieved by a film having a scattering property, an especially widefield-of-view angle is not required in the mode of liquid crystal.Therefore, the range of selecting a liquid crystal mode can be widened.That is, the liquid crystal mode may be freely chosen from bright modesof high-speed response and be used. In particular, in the case of aperpendicularly oriented mode, since the mode can be made brightregardless of the shift-down direction, as far as liquid crystalmolecules can be shifted down by application of voltage, in addition tothat the mode has high contrast in principle, there is no need tocontrol the rubbing and to carry out other orientation control, whereinthere are other advantages in that the degree of freedom can be widenedin designing of pixels, and the liquid crystal materials can be widelyselected. In addition, even in the case where a so-called amorphous TNmode not requiring any rubbing, which is the TN mode instead of beingperpendicularly oriented, is employed, there is a large advantage byvirtue of the same reason as those in the above. Still further, in amode in which liquid crystal is made erect by applying voltage in thedirection perpendicular to liquid crystal (liquid crystal in whichliquid crystal molecules are oriented in various directions in theazimuth direction) that is homogeneously oriented by using ahorizontally oriented film without rubbing, there is a large advantageby virtue of the reason similar thereto.

[0081] Also, in the invention, the color filtering layer is disposed inliquid crystal cells on the first substrate. Therefore, in particular,in the case of a so-called active matrix drive, in which liquid crystalis driven by a switching element such as a thin-film transistor (TFT),since the switching element to drive the color filtering layer andanother switching element to drive the liquid crystal can be formed onthe same first substrate, no alignment is required between two upper andlower substrates. This is remarkably advantageous in view of production.

[0082] Further, although the substrates are generally made of glasssubstrates, plastic substrates may be used to lighten the total weight.

[0083] Also, the optical absorbing layer may be of any type, which isblack, and may be concurrently made of a black matrix material. That is,a metal such as chrome, a film of a metal whose surface is roughed so asnot to reflect light, or a black paint so called black resist, or resinincluding a pigment, etc., may be used.

[0084] In addition, in a liquid crystal display according to theinvention, orientation and division are not necessarily required in theliquid crystal cells. However, the orientation and division may becarried out in the case where it is better to use oriented and dividedliquid crystal cells in view of the field-of-view angle characteristicsin the case where being used in a narrow field-of-view angle, in view ofuniformity of brightness in the panel plane, and a response rate, etc.

[0085] In this case, where it is assumed that the electrode (pixelelectrode) disposed on the surface of a liquid crystal layer at thefirst substrate side, that is, the surface at the rearward side in theincident direction of light is circular or equilaterally polygonal tohave more sides than those of a triangle, and that the electrode (commonelectrode) disposed on the surface of a liquid crystal layer at thesecond substrate side, that is, the surface at the forward side in theincident direction of light is larger in area than that of the pixelelectrode and is formed at a position where it can cover the entirepixel electrode, it is possible to easily orient and divide liquidcrystal cells without increasing the processes of production. Also, itis preferable that said common electrode is formed on almost the entiresurface of the second substrate. Further, it is preferable that, at thepositions equidistant from each other in the circumference or at thecorners of an equilateral polygon, the pixel electrode is shaped so thata cut is formed, a projection protruding outward is formed, or a recessis formed at a part of said pixel electrode, or so that it is formed ofa combination thereof.

[0086] Still further, it becomes possible to further secure the initialorientation of liquid crystal by making a polymerizable monomer oroligomer, which is mixed in liquid crystal at a slight ratio,macromolecular after having controlled the initial orientation byapplying voltage between the common electrode and pixel electrode. Whencontrolling the initial orientation, the temperature may be loweredwhile applying voltage between the common electrode and pixel electrodeafter having made the liquid crystal layer isotropic by heating, andonly voltage may be applied between the common electrode and pixelelectrode at room temperature. Also, a monomer reaction may be broughtabout prior to heating the liquid crystal layer to make it isotropic,during heating the same or after having cooled it down. Even in the caseof controlling the initial orientation by applying voltage between thecommon electrode and pixel electrode at room temperature, amacromolecular reaction may be brought about prior to the application ofvoltage, or may be brought about after the application thereof. At thistime, since the orientation and division are enabled in the form ofnormal drive, it is not necessary to provide a process of applyingvoltage to the second electrode as in the prior art example 2.

[0087] In addition, a method for producing a reflection liquid crystaldisplay according to the invention carries out control of a pre-tiltangle based on the division profile, using an optical orientation methodin advance on substrates, whereby the control of the initial orientationcan be made remarkably secure. Thereby, by virtue of a synergetic effectof an oblique electric field and a pre-tilt angle, the divisionorientation can be further remarkably effectively achieved than eitherof the processes. For example, a substance having a functional group bywhich orientation of liquid crystal can be controlled by polarizationsuch as a cinnamic group, or a macromolecule in which a photosensitivegroup is polymerized by irradiation of polarized light as described inthe AM-LCD 1996/IDW 1996 Digest of Technical Papers, Page 337 is used asan orientation film, and polarized light is irradiated from a diagonaldirection via a mask at respective parts so that a pre-tilt angle isgiven in a direction along the division profile. In this case, since thenumber of times of operation for optical orientation is increased if thenumber of sides of a polygon is large, a polygon from an octagon to atriangle is preferable.

[0088] Such a method for division and orientation has been publiclyknown. However, in such a case, by making a polymerizable monomer oroligomer, which is mixed in liquid crystal at a slight ratio,macromolecular, it is possible to further securely maintain the divisionwhen driving.

[0089] As a monomer or oligomer used in the present invention, any oneof an optically hardening monomer, thermally hardening monomer, andoligomer thereof may be used, and the monomer or oligomer may includeother constituents as long as they include these. The optical hardeningmonomer or oligomer is not limited to those that not only react tovisible light beams but may include those that react by an ultravioletray, wherein an ultraviolet ray hardening monomer is particularlypreferable in view of ease in operation.

[0090] Also, a macromolecular compound used in the invention may be acompound having a structure that is similar to that of liquid crystalmolecules including monomer and oligomer having liquid crystalinity.However, since the macromolecular compound is not necessarily used toorient liquid crystal, it may be a compound having flexibility, whichhas an alkylene chain. Also, it may be a compound belonging to amono-functional group monomer, or may be a monomer having amulti-functional group such as a double-functional group or tri- or morefunctional group.

[0091] As optically- or ultraviolet ray-hardening monomers used in theinvention, for example, mono-functional acrylate compounds may be used,which are 2-ethylhexyl acrylate, butylethyl acrylate, butoxyethylacrylate, 2-cyanoethyl acrylate, benzyl acrylate, cyclohexyl acrylate,2-hydroxy propyl acrylate, 2-ethoxyethyl acrylate, N,N-diethylaminoethylacrylate, N,N-dimethylaminoethyl acrylate, dichlopentanyl acrylate,dichlopentanyl acrylate, glycizyl acrylate, tetrahydro furfurylacrylate, isobonyl acrylate, isodecyl acrylate, lauryl acrylate,morpholine acrylate, phenoxyethyl acrylate, phenoxydiethlene glycolacrylate, 2,2,2-trifluoroehtyl acrylate, 2,2,3,3,3-pentafluoropropylacrylate, 2,2,3,3-tetrafluoropropyl acrylate, and2,2,3,4,4,4-hexafluorobutyl acrylate, etc.

[0092] Also, mono-functional methacrylate compounds may be used, whichare 2-ethylhexyl methacrylate, butylethyl methacrylate, butoxyethylmethacrylate, 2-cyanoethylmethacrylate, benzyl methacrylate, cyclohexylmethacrylate, 2-hydroxypropyl methacrylate, 2-ethoxyethyl methacrylate,N,N-diethylaminotheyl methacrylate, N,N-diethylaminoethyl methacrylate,dicyclopentanyl methacrylate, dicyclopentanyl methacrylate, glycizylmethacrylate, tetrahydrofurfuryl methacrylate, isobonyl methacrylate,isodecyl methacrylate, lauryl methacrylate, morpholine methacrylate,phenoxyethyl methacrylate, phenoxydiethylene glycol methacrylate,2,2,2-trifluoroethyl methacrylate, 2,2,3,3-tetrafluoropropylmethacrylate, 2,2,3,3,3-pentafluoropropyl methacrylate, and2,2,3,4,4,4-hexafluorobutyl methacrylate, etc.

[0093] Further, multi-functional acrylate compounds may be used, whichare 4,4′-viphenyl diacrylate, diethylstyrbestrol diacrylate,1,4-bisacryloyl oxybenzene, 4,4′-bisacryloyl oxydiphenylether,4,4′-bisacryloyl oxydiphenyl methane,3,9-bis[1,1-dimethyl-2-acryloyloxyethyl]-2,4,8,10-tetraspiro[5,5]undecane,α,α′-bis[4-acryloyl oxyphenyl]-1,4-diisopropyl benzene, 1,4-bisacryloyloxytetrafluorobenzene, 4,4′-bisacryloyl oxyoctafuloro biphenyl,diethelene glycol diacrylate, 1,4-butanedioldiacrylate, 1,3-buthyleneglycol diacrylate, dicyclo pentanyl diacrylate, glycerol diacrylate,1,6-hexanediol diacrylate, neopentyl glycol diacrylate, tetraethyleneglycol diacrylate, trimethylol propane triacrylate, pentaerythritoltetraacrylate, pentaerythritol triacrylate, ditrumethylol propanetetraacrylate, dipentaerythritol hexaacrylate, dipentaerythritolmonohydroxypentaacrylate, 4,4′-diacryloyl oxystilbene, 4,4′-diacryloyloxydimethyl stilbene, 4,4′-diacryloyl oxydiethyl stilbene,4,4′-diacryloyl oxydipropyl stilbene, 4,4′-diacryloyl oxydibutylstilbene, 4,4′-diacryloyl oxydipentyl stilbene, 4,4′-diacryloyloxydihexyl stilbene, 4,4′-diacryloyl oxydifluorostilbene,2,2,3,3,4,4-hexafluoropentandiol-1,5-diacrylate,1,1,2,2,3,3-hexafluoropropyl-1,3-diacrylate, and urethane acrylateoligomer, etc.

[0094] Still further, multi-functional methacrylate compounds such asdiethylene glycol dimethacrylate, 1,4-butanediol dimethacrylate,1,3-butylene glycol dimethacrylate, dicyclopentanyl dimethacrylate,glycerol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycoldimethacrylate, tetraethylene glycol dimethacrylate, trimethylol propanetrimethacrylate, pentaerythritol tetramethacrylate, pentaerythritoltrimethacrylate, ditrimethylol propanetetra methacrylate,dipentaerythritol hexamethacrylate, dipentaerythritol monohydroxypentamethacrylate, 2,2,3,3,4,4-hexafluoropenatdiol-1,5-dimethacrylate,and urethane methacrylate oligomer, etc., other styrene, aminostyrene,and vinyl acetate, etc., may be available. But, the optically andultraviolet-ray hardening monomers are not limited to the above.

[0095] Since the drive voltage of elements of the invention isinfluenced by a mutual action at the boundary phase between amacromolecular material and liquid crystal material, the monomer may bea macromolecular compound including a fluorine atom. As such amacromolecular compound, macromolecular compounds may be listed, whichare synthesized with a compound including2,2,3,3,4,4-hexaafluoropentanediol-1,5-diacrylate,1,1,2,2,3,3-hexafluoropropyl-1,3-diacrylate, 2,2,2-trifluoroethylacrylate, 2,2,3,3,3-penta fluoro propyl acrylate,2,2,3,3-tetraafluoropropyl acrylate, 2,2,3,4,4,4-hexafluorobutylacrylate, 2,2,2-trifluoroethylmethacrylate,2,2,3,3-tetrafluoropropylmethacrylate, 2,2,3,4,4,4-hexafluorobutylmethacrylate, and urethane acrylate oligomer, etc., but themacromolecular compounds are not limited to these.

[0096] In the case where an optically hardening or ultraviolet-rayhardening monomer is used as a macromolecular compound used for theinvention, an initiator for light or ultraviolet ray may be used.Various types of initiators may be used. For example, acetophenon-basedinitiators such as 2,2-diethoxy acetophenon,2-hydroxy-2-methyl-1-phenyl-1-on,1-(4-isopropylphenyl)-2-hydroxy-2-methylpropane-1-on, and1-(4-dodecylphenyl)-2-hydroxy-2-methylpropane-1-on, etc., benzoin-basedinitiators such as benzoinmethylether, benzoinethylether, and benzyldimethyl ketal, etc., benzophenon-based initiators such as benzophenon,benzoil benzoic acid, 4-phenyl benzophenon, and3,3-dimethyl-4-methoxybenzophenon, etc., thioxanson-based initiatorssuch as thioxanson, 2-chlorthiozanson, and 2-methylthioxanson, etc.,diazonium salt-based initiators, sulfonium salt-based initiators,iodonium salt-based initiators, and selnium salt-based initiators, etc.,may be used.

[0097] Further, as regards the division, there is no problem if asufficient interval is secured between pixels. However, in a case wherepixels approach each other particularly in order to secure a conveniencein design, so-called dot-inverted drive in which the polarities ofvoltage applied onto adjacent pixels is carried out when driving thepixels, wherein since a state of occurrence of oblique electric fieldsis improved, better division can be obtained.

[0098] In addition, pixels can be reset to be returned to a black statein a frame and driven in order to improve the separation or cut ofmoving pictures. In normal cathode ray tubes (CRT), the display screenshines at high brightness for several milliseconds, and the displayscreen is kept black for the remaining time of one frame (16.6milliseconds). Therefore, when displaying a moving picture, there is atime, at which nothing is seen, between a moving picture and anothermoving picture. To the contrary, in liquid crystal display, the screenis kept shinning for 16.6 milliseconds at the same brightness.Therefore, an overlapping portion can be sensitively seen between amoving picture and another moving picture when a picture moves.Therefore, at a glance, it seems that moving pictures are out of focus.At this time, if a black display is inserted at the end portion of the16.6 milliseconds, the vagueness can be reduced, and the moving picturescan be smoothly seen. This means that separation or cut of movingpictures is improved.

[0099] Hereinafter, a detailed description is given of embodiments ofthe invention with reference to the accompanying drawings. FIG. 3 is asectional view showing a reflection liquid crystal display according toa first embodiment of the invention.

[0100] As shown in FIG. 3, an optical absorption plate 106 is disposedon a first substrate 107, and a reflection layer 105 besides acting as acolor filter (color filtering layer), which consists of a cholestericmaterial layer and concurrently operates as a color filter and areflection plate, is disposed on the optical absorption layer 106. Atransparent substrate 103 acting as a second substrate is disposed onthe reflection layer 105 besides acting as a color filter with a liquidcrystal layer 104 placed therebetween. The transparent substrate 103 isdisposed so as to be opposed to the first substrate 107, so that thetransparent substrate 103 comes to the forward side of the firstsubstrate 107 in the incident direction of light. And, a wide-bandquarter-wavelength plate 102 is disposed on the surface at the forwardside in the light-incident direction of the transparent substrate 103,and a polarization plate 101 is further disposed on the surface at theforward side in the light incident direction of the quarter-wavelengthplate. The polarization plate 101 is disposed so that the direction ofthe transmission axis thereof is formed at 45 degrees with respect tothe direction of the optical axis of the quarter-wavelength plate 102.Also, the liquid crystal layer 104 is formed so that the retardation,when appointed voltage is applied, varies by half a wavelength.

[0101] In principle, as described above, incident light 100 that haspassed through the polarization plate 101 and wide-bandquarter-wavelength plate 102 is converted to a circular-polarized lightby the transmission axis of the polarization plate 101 and optical axisof the quarter-wavelength plate being disposed so that they are inclinedat 45 degrees. And, whether the optical axis is disposed so as to beinclined clockwise (rightward) to 45 degrees with respect to thetransmission axis of the polarization plate 102 or counterclockwise(leftward) to 45 degrees with respect thereto decide that the lightwhich has passed through the polarization plate 101 and wide-bandquarter-wavelength plate 102 becomes a rightward circular-polarizedlight or leftward circular-polarized light.

[0102] Hereinafter, a description is given of an action of theembodiment where the polarization plate 101 and quarter-wavelength plate102 are established so as to make the light become, for example,rightward circular-polarized light. FIG. 4 is an exemplary view showingthe transmission axis direction of the quarter-wavelength plate and theoptical axis direction of the polarization plate in the case where theincident light becomes a rightward circular-polarized light. In thepresent embodiment, as shown in FIG. 4, the polarization plate 101 andwide-band quarter-wavelength wavelength plate 102 are disposed so thatthe optical axis direction 902 of the quarter-wavelength plate 102 isinclined clockwise to 45 degrees with respect to the transmission axisdirection 901 of the polarization plate 101, and the reflection layer105 besides acting as a color filter of the cholesteric material layeris made into a right-twisted cholesteric material layer.

[0103] Even in any mode, normally, the liquid crystal layer 104 bringsabout the same action as that of the half-wavelength plate by turning iton or off. That is, the phase difference is varied between 0 and π inresponse to applied voltage. The incident light 100 becomes a rightwardcircular-polarized light by passing through the polarization plate 101and wide-band quarter-wavelength plate 102. In this case, when the phasedifference of the liquid crystal layer 104 is 0, the rightwardcircular-polarized light that has passed through the liquid crystallayer 104 enters the reflection layer 105 besides acting as a colorfilter consisting of a cholesteric material layer as it is a rightwardcircular-polarized light. Since the cholesteric material layer isright-twisted, light corresponding to a pitch of the cholestericmaterial layer is reflected and becomes a rightward circular-polarizedlight. Since the phase difference of the liquid crystal layer 104 is 0,the rightward circular-polarized light passes through the liquid crystallayer 104 as it is rightward circular-polarized light, and furtherenters the wide-band quarter-wavelength plate 102, wherein it isconverted to a linear-polarized light that oscillates in thetransmission axis direction of the polarization plate 101. Therefore,the linear-polarized light is able to pass through the polarizationplate 101 and becomes an outgoing light 130. That is, with the pixel, acolor corresponding to the pitch of the cholesteric material layer isdisplayed.

[0104] On the other hand, when the phase difference of the liquidcrystal layer 104 is made into π by applying voltage to the liquidcrystal layer 104, the light that has passed through thequarter-wavelength plate 102 and has become rightward circular-polarizedlight is converted to leftward circular-polarized light by the liquidcrystal layer 104. And, the leftward circular-polarized light enters thereflection layer 105 besides acting as a color filter consisting of acholesteric material layer. Since the cholesteric material layer isright-twisted, the leftward circular-polarized light passes through thereflection layer 105 besides acting as a color filter. Therefore, it isabsorbed by the optical absorption layer, wherein black is displayedwith the pixel.

[0105] In the embodiment, bright and dark display of pixels can becontrolled by varying the amount of reflection light by changing theretardation of the liquid crystal layer 104. In order to vary the amountof reflection light, there is a method for changing application voltageby using a threshold-free type ferroelectric liquid crystal or a methodfor making the retardation different in one liquid crystal cell bychanging the electrode area, which is used to apply voltage to theliquid crystal layer in the liquid crystal cell. Thus, where thecholesteric material layer is used as a reflection layer 105 besidesacting as a color filter, the reflection light has no dependency inrelation to the azimuth angle direction since the reflection light is acircular-polarized light when pixels are bright. Therefore, even ifliquid crystal is oriented in any form, a bright display similar to theabove can be secured at all times. That is, it is not necessary tocontrol the direction of orientation in the plane of a directionparallel to the substrate of a liquid crystal. Therefore, in thehorizontal orientation mode, it does not become necessary to regulatethe initial orientation by rubbing. Also, even in the perpendicularorientation mode, it does not become necessary to control the directionalong which liquid crystal molecules are shifted down, wherein areflection liquid crystal display for which production is facilitatedcan be proposed. Further, since the reflection layer 105 besides actingas a color filter in which a cholesteric material layer is used does notabsorb any light, there is no case where light is converted to heat evenif the intensity of irradiation light 100 is increased, and membersdeteriorate. Also, since the layer 105 does not absorb any light, abright reflection liquid crystal display can be obtained.

[0106] In addition, although glass substrates are usually used for thetransparent substrate 103 and the first substrate 107, plasticsubstrates may be used in view of weight, flexibility, etc. Where atransparent substrate is used as the first substrate 107, the opticalabsorption layer 106 may be provided at the side opposed to the side atwhich the liquid crystal layer 104 of the first substrate 107 is placed.Also, as in the present embodiment, where the optical absorption layer106 is formed inside the liquid crystal cell on the first substrate 107,a non-transparent thin plate such as a stainless steel foil may be usedas the first substrate 107. Further, in the embodiment, although thepolarization plate 101 and a wide-band quarter-wavelength plate 102 aredisposed outside the liquid crystal cells, that is, on the surface atthe forward side in the light-incident direction of the transparentsubstrate 103, it may be placed between the transparent substrate 103and the liquid crystal layer 104 thereon. Still further, the transparentsubstrate 103 may be disposed between the polarization plate 101 and thequarter-wavelength plate 102.

[0107] Also, the invention is featured in that a reflection layer 105besides acting as a color filter is disposed at the side where theliquid crystal layer 104 of the first substrate 107 exists. That is, thereflection layer 105 besides acting as a color filter is formed on thefirst substrate 107 in the liquid crystal cells. Normally, wiring (notillustrated) by which liquid crystal of respective pixels is driven isformed around the respective liquid crystal pixels. It is necessary toaccurately align the pixels of the respective pixels with the colorelements, and necessary to adhere them altogether. However, in theinvention, since the reflection layer 105 besides acting as a colorfilter is disposed on the first substrate 107 in a liquid crystal cell,the alignment can be made easier, wherein the ratio of opening isexcellent, and it is possible to provide a reflection liquid crystaldisplay whose production is facilitated. Besides, since there is noelement, for which alignment is required, in the transparent substrate103 acting as the second substrate at the side opposed thereto,alignment is no longer required for both the first substrate 107 andtransparent substrate 103, wherein the production thereof can be mucheasier in comparison with a normal reflection liquid crystal display inwhich a reflection layer besides acting as a color filter is disposed atthe transparent substrate side.

[0108] Next, a description is given of a second embodiment of theinvention. FIG. 5 is a sectional view showing a reflection liquidcrystal display according to the second embodiment of the invention. Theembodiment is such that a film having a scattering property is furtherdisposed on the display surface of a reflection liquid crystal displayaccording to the first embodiment. As described with respect to thefirst embodiment, a transparent substrate 203 acting as a secondsubstrate is opposed to a first substrate 207 with a liquid crystallayer 204 placed therebetween, and the transparent substrate 203 isdisposed further forward in the incident direction of light from thefirst substrate 207. An optical absorption layer 206 is disposed on thesurface at the forward side in the light-incident direction of the firstsubstrate 207, that is in the liquid crystal cells. Further, areflection layer 205 besides acting as a color filter that consists of acholesteric material layer is disposed on the surface at the forwardside in the light-incident direction of the optical absorption layer206. In addition, a wide-band quarter-wavelength plate 202, on which apolarization plate 201 is disposed, is disposed on the surface at theforward side in the light-incident direction of the transparentsubstrate 203, that is, outside the liquid crystal cells. And, in thepresent embodiment, a scattering film 208 is disposed on thepolarization plate 201.

[0109] As in the first embodiment, the present embodiment has advantagesby which bright display can be brought about, and production can befacilitated. Further, although, in the first embodiment, there is a casewhere the field-of-view angle is not sufficient according to a certainpurpose since the directivity of selection reflection of the cholestericmaterial layer is intensive, it is possible to easily secure a widefield-of-view angle in the embodiment since the scattering film 208 isprovided. And, by attaching and detaching the scattering film, it ispossible to easily change over a wide field-of-view angle and a narrowfield-of-view angle or vice versa.

[0110] Next, a further detailed description is given of effects that arebrought about by disposing a scattering film in the embodiment. Also, inthe embodiment, a point in which the amount of reflection light iscontrolled by voltage applied onto the liquid crystal layer 204 iscompletely the same as that of the first embodiment. Incident light 200that enters the polarization plate 201 and outgoing light 230 radiatingfrom the polarization plate 201 are caused to scatter in response to thescattering properties of the scattering film 208.

[0111] An attempt to secure a wide field-of-view angle can be carriedout by adjusting the scattering angle. It is possible to design ascattering film 208 that permits only light incident from an appointedangle to be transmitted and transmits only positive reflectionconstituents. Such a scattering film 208 may be formed by a method foroptical polymerization from an oblique direction. If the scattering film208 is designed so that the light that has entered at an angle of thepositive reflection constituent and the pitch of the cholesteric liquidcrystal meet Bragg's reflection conditions corresponding to the threeprime colors, the respective colors can be displayed. At this time, itis common that different colors are juxtaposed in different pixels.Also, since the reflection light has passed through the scattering film208, it is adequately scattered, and so-called paper white free from anyglittering can be achieved. Further, when forming a scattering film 208,it is possible to adjust the field-of-view angle by adjusting thedirectivity of the direction corresponding to the reflection light. As aresult, a plurality of scattering films 208 whose directivity in thereflection direction differs are prepared, wherein, by only re-attachingthese, it is possible to easily change the field-of-view angle.

[0112] Conventionally, where an attempt is made to widen thefield-of-view angle of a reflection liquid crystal display by using thescattering film, in the case of a transmission type, influence ofadjacent pixels cannot be removed, wherein there was a problem ofparallax in which letters are seen to be doubled. However, in theembodiment, for the two reasons which are a reflection layer 205 besidesacting as a color filter consisting of a cholesteric material layerbeing close to the liquid crystal layer 204 and the directivity ofselection reflection of the cholesteric material layer being high, thereis an advantage in that no problem of parallax occurs in practice evenif the field-of-view angle is widened.

[0113] Next, a description is given of a third embodiment of theinvention. The embodiment is such that a macromolecular dispersionliquid crystal layer is used instead of a scattering film 208 in thesecond embodiment. FIG. 6A and FIG. 6B are sectional views showing areflection liquid crystal display according to the third embodiment ofthe invention, wherein FIG. 6A shows a state where no voltage is appliedonto a macromolecular dispersion liquid crystal layer, and FIG. 6B showsa state where voltage is applied onto a macromolecular dispersion liquidcrystal layer. As shown in FIG. 6A and FIG. 6B, a transparent substrate303, which is disposed as a second substrate, is opposed to a firstsubstrate 307 with a liquid crystal layer 304 placed therebetween. Thetransparent substrate 303 is disposed so that it comes forward to thefirst substrate 307 in the light-incident direction. And, an opticalabsorption layer 306 is formed on the surface at the forward side in thelight-incident direction of the first substrate 307, and a reflectionlayer 305 besides acting as a color filter consisting of a cholestericmaterial layer is disposed on the surface at the forward side of theoptical absorption layer 306 in the light-incident direction. Also, awide-band quarter-wavelength plate 302 is disposed on the surface at theforward side of the light-incident direction of the transparentsubstrate 303 while a polarization plate 301 is disposed on the surfaceat the forward side of the light-incident direction of thequarter-wavelength plate 302. And, in the embodiment, a macromoleculardispersion liquid crystal layer 308 is disposed on the surface at theforward side of the light-incident direction of the polarization plate301. A power source 309 is connected to the macromolecular dispersionliquid crystal layer 308, thereby controlling voltage that is appliedonto the macromolecular dispersion liquid crystal 308.

[0114] Where incident light 300 is reflected by a reflection layer 305besides acting as a color filter based on the principle similar to thatof the first embodiment, it becomes light radiating from themacromolecular dispersion liquid crystal layer 308. The macromoleculardispersion liquid crystal layer 308 is such that liquid crystal dropsare dispersed in a macromolecular medium. Usually, when no voltage isapplied thereto, the outgoing light 330 a is scattered, as shown in FIG.6A, because the refractive index of the macromolecules in the medium isnot coincident with the mean refractive index of liquid crystal. On theother hand, if voltage is applied thereto, the orientations of liquidcrystal in the liquid crystal drops are lined up, wherein the refractiveindex of the macromolecular medium becomes almost the same as that ofthe liquid crystal to bring about a transparent state.

[0115] For example, if the pitch of the reflection layer 305 besidesacting as a color filter consisting of a cholesteric material layer isformed so that it can meet Bragg's reflection conditions at an appointedwavelength with respect to the incident light 300 from an appointedangle, reflection light of an appointed color is reflected into thedirection of selection reflection where the state is transparent due toapplication of voltage onto the macromolecular dispersion liquid crystallayer 308, it can pass through the macromolecular dispersion liquidcrystal layer 308 and becomes outgoing light 330 b. In addition, thereflection layer besides acting as a color filter has a highdirectivity. Due to these reasons, a narrow field-of-view angle can beobtained. On the other hand, in a state where no voltage is applied, asshown in FIG. 6A, the outgoing light 330 a is scattered, and a widefield-of-view angle can be obtained in response to a degree of thescattering. Thus, it is possible to electrically change over a widefield-of-view angle and a narrow field-of-view angle.

[0116] As a method for forming a macromolecular dispersion liquidcrystal layer 308, a mixture of photosensitive monomer and liquidcrystal is poured between the transparent substrate (not illustrated) inwhich a transparent electrode such as ITO is formed, and themacromolecular dispersion liquid crystal 308, whereby, by irradiating anultraviolet ray, the monomer is polymerized, resulting in phaseseparation. Also, the macromolecular dispersion liquid crystal layer maybe used in a state where it is placed in the transparent substrate, andsince the polymerized macromolecular dispersion liquid crystal layerbecomes a considerably firm film, another macromolecular dispersionliquid crystal layer film is prepared, wherein a transparent electrodemay be formed on both sides thereof. Further, not only a glass substratebut also a plastic substrate may be used as a transparent substrate.

[0117] When forming a macromolecular dispersion liquid crystal layer308, light polymerization is not carried out by uniform light but byinterference light, wherein it is possible to control a place wheremacromolecules are polymerized, and it is possible to set the scatteringdirection of light by utilizing the above.

[0118] Further, a scattering film similar to that of the secondembodiment may be disposed on the macromolecular dispersion liquidcrystal layer 308. For example, by designing so that light transmits atonly the incident angle and angle of positive reflection constituentscorresponding to the incident angle, a film for which the scatteringproperty is suppressed is formed, and the film is provided on themacromolecular dispersion liquid crystal layer 308. And, themacromolecular dispersion liquid crystal layer 308 gives only a featureof carrying out changeover of whether or not the scattering property isprovided. Thus, display in which color separation is more satisfactorycan be obtained in the case where the scattering film and macromoleculardispersion liquid crystal layer 308 are concurrently used than in thecase where only the macromolecular dispersion liquid crystal layer 308is used.

[0119] Next, a description is given of a fourth embodiment according tothe invention. FIG. 7 is a sectional view showing a liquid crystaldisplay element according to the fourth embodiment of the invention. Inthe embodiment, a cholesteric material layer having an inverted twist ofthe cholesteric material layer, which is used in the reflection layerbesides acting as a color filter, is laminated so as to correspond tothe three prime colors instead of the polarization plate and wide-bandquarter-wavelength plate in the first embodiment through the thirdembodiment.

[0120] That is, as shown in FIG. 7, a liquid crystal layer 404 isdisposed between the first substrate 407 and a transparent substrate403, corresponding to the first substrate 407, which is provided as asecond substrate so as to come to the forward side of the incidentdirection of light. An optical absorbing layer 406 is disposed on thefirst substrate 407 in the liquid crystal cell, and a cholestericmaterial layer 405 that is a reflection layer besides acting as a colorfilter is disposed on the surface at the forward side of the incidentdirection of light of the optical absorbing layer 406. And, cholestericmaterial layers 409, 410 and 411, which have an inverted twist of thatof the cholesteric material layer 405, are disposed on the transparentsubstrate 403 outside the liquid crystal cell. These cholestericmaterial layers 409, 410, and 411 are made into a three-layeredlaminated body corresponding to the three prime colors, and areinstalled at the side opposite to the side on which the liquid crystallayer 404 is placed on the transparent substrate 403. The twistingdirection of the cholesteric material layers 409, 410 and 411 of thethree prime colors, which are disposed outside the liquid crystal cell,is reverse of that of the cholesteric material layer 405 inside theliquid crystal cell. In addition, the up and down relationship betweencolor layers in view of structure does not regard the capacity.

[0121] The color of the cholesteric material layer is determined by thepitch of twist of the cholesteric material layer. Therefore, in thecholesteric material layers 409, 410 and 411, the pitches of respectivetwist correspond to red (R), green (G), and blue (B). At this time, thepitches may gradually change and may be formed so as to correspond tothe wavelength of the entire visible area. Since these layers do notneed to change colors position by position, these layers may be formedas a single film, for example, by the material and method, which aredescribed in R. Mauer, D. Andrejewski, F -H. Kreuzer, A. Miller,SID90DIGEST, pages 110 to 112 (1990), and may be adhered on thetransparent substrate 403. Also, a color filtering layer consisting of acholesteric material layer 405 may be formed of a liquid crystal layer,having a photosensitive group as described in Liquid Crystals, Vol.No.18, page 319 (1995), in which the chiral pitch is adjusted to anappointed color.

[0122] The cholesteric material layer 405 inside the liquid crystal cellmay be formed of the material and method, which are described in R.Mauer, D. Andrejewski, F -H. Kreuzer, A. Miller, SID90DIGEST, Pages 110to 112 (1990), as in the cholesteric material layers 409, 410, and 411outside the liquid crystal cell. Also, since it is necessary fordifferent color layers to be formed pixel by pixel in the cholestericmaterial layer 405, it is possible to produce the layer 405 by using thesame lithography as that for forming a normal absorption type colorfilter. At this time, since the material itself that becomes thecholesteric material layer 405 is photosensitive, the lithography iscomparatively easy.

[0123] It is possible to adequately select the pitch and twistingdirection of the cholesteric material layer 405 in compliance with thequantity of a chiral agent to be mixed and its type. If an orientationfilm by which horizontal orientation is achieved is coated on theoptical absorption layer 406, it is possible to form a cholestericmaterial layer 405 by which the twisting axis becomes perpendicular tothe substrate. As necessary, such a method may be employed, by which anoptical orientation film to rub the orientation film is formed, and theorientation of the cholesteric liquid crystal is controlled on theboundary phase by irradiation of polarized light.

[0124] Also, it is necessary to coat a liquid crystal orientation filmon the cholesteric material layer in order to control the orientation ofliquid crystal in the liquid crystal layer 404. At this time, it ishighly recommended that burning of the orientation film is carried outat a low temperature of 180° C. or so, so that the state of liquidcrystal orientation of the cholesteric material layer 405 is notdisturbed. Also, it is recommended that no rubbing be performed due tosimilar reasons. Although rubbing may be performed when it is necessaryto control the orientation of liquid crystal, it is preferable that theorientation is controlled by irradiation of polarized light by using anoptical orientation film.

[0125] Next, a description is given of actions of the embodiment. Forexample, where it is assumed that the cholesteric material layer 405inside the liquid crystal cell is right-twisted as in the firstembodiment, all the cholesteric material layers 409, 410 and 411 of thethree prime colors are left-twisted. When incident light passes throughthe three prime color laminated cholesteric material layers 409, 410 and4110 from the exterior, leftward circular-polarized light of the lightof wavelengths corresponding to the three prime colors R, G and B isreflected by the cholesteric material layer, and only the rightwardcircular-polarized light of the three prime colors is permitted to enterthe liquid crystal layer 404. And, by the principle similar to that ofthe first embodiment, when the phase difference of the liquid crystallayer 404 is 0, the rightward circular-polarized light enters thereflection layer besides acting as a color filter consisting of acholesteric material layer 405 as it is, and only light of the colorcorresponding to the pitch of the cholesteric material layer 405 isreflected as rightward circular-polarized light. Also, the other lightpasses through the cholesteric material layer 405 and is absorbed by theoptical absorption layer 406. After that, the rightwardcircular-polarized light, which is the reflection light from thecholesteric material layer 405, passes through a liquid crystal layer404 without being subjected to any change since the phase difference ofthe liquid crystal layer 404 is 0, and enters the cholesteric materiallayers 409, 410 and 411, which are laminated in three prime colors, asit is the rightward circular-polarized light. Since the cholestericmaterial layers 409, 410 and 411 are left-twisted, the rightwardcircular-polarized light passes through as it is, and is caused toradiate from the scattering film 408, thereby becoming outgoing light430. The outgoing light 430 is scattered by the scattering film 408, isspread to an adequate angle and reaches the observer's eyes. Thus, acolor corresponding to the pitch of the cholesteric material layer 405is displayed at the pixel. On the other hand, by the principle similarto that of the first embodiment, where the phase difference of liquidcrystal is π, the light from the liquid crystal layer 404 becomesleftward circular-polarized light. It passes through the cholestericmaterial layer 405 and is absorbed by the optical absorption layer 406,whereby black is displayed at the pixel.

[0126] As in the first embodiment through the third embodiment, in thefourth embodiment, the amount of reflection light can be controlled byvarying the retardation of the liquid crystal layer 404. Also, since thereflection light is circular-polarized light without fail when being ina bright state, the reflection light has no dependency on the azimuthangle direction, and a bright display can be brought about even if theliquid crystal is oriented in any azimuth angle direction, which arecompletely the same as those in the first embodiment through the thirdembodiment. Further, since the scope of an incidence angle that meetsBragg's conditions is narrow in the case of selection reflection inwhich the cholesteric material layer 405 is used, the embodiment isfeatured in that the directivity of incident light and reflection isexcellent. Still further, since it is possible to control the direction,which meets Bragg's conditions, by the size of pitch, it is advantageousin that it is easier to control the directivity in comparison with thecase where a wide-band quarter-wavelength plate is used.

[0127] Next, a description is given of a fifth embodiment according tothe invention. FIG. 8 is a sectional view showing a reflection liquidcrystal display according to the fifth embodiment of the invention. Inthe fourth embodiment, cholesteric material layers, which has aninverted twist of the cholesteric material layer that is used for areflection layer besides acting as a color filter, is laminated so as tocorrespond to the three prime colors outside of the liquid crystal cell.However, as shown in FIG. 8, in the fifth embodiment, the threeprime-color laminated body is disposed inside the liquid crystal cell,that is, the surface at the rearward side in the incident direction oflight in the transparent substrate 503 acting as the second substrate.All the other construction is the same as that of the fourth embodiment.

[0128] In the embodiment, a body 512, laminated in three prime colors,of cholesteric material layers 509, 510 and 511 having an inverted twistof that of the cholesteric material layer 505 used in a reflection layerbesides acting as a color filter is disposed on the surface, at a liquidcrystal layer 504 side, of a transparent substrate 503 which is disposedas the second substrate. The principle of display and production methodare the same as those of the fourth embodiment. However, the laminatedbody 512 in which cholesteric material layers 509, 510 and 511 forconverting natural light to rightward circular-polarized light (orleftward circular-polarized light) are laminated so as to correspond tothe three prime colors is opposed to a cholesteric material layer 505used for a reflection layer besides acting as a color filter with aliquid crystal layer whose thickness is several micrometers (μm) placedtherebetween. Therefore, the embodiment is remarkably advantageous inview of parallax.

[0129] Next, a description is given of a sixth embodiment according tothe invention. FIG. 9A is a plan view showing a reflection liquidcrystal display according to the sixth embodiment of the invention, FIG.9B is a sectional view taken along the line A-A of FIG. 9A. FIG. 9A and9B shows a detailed structure in the case where liquid crystal is drivenby an active element.

[0130] As shown in FIG. 9A, a picture signal line 620 a that is a dataline is formed on a first substrate 607, and a drain electrode 620 b isconnected thereto. That is, the drain electrode 620 is formed by partialextension of the picture signal line 620 a. Also, a scanning signal line622 a is formed so as to cross the picture signal line 620 a, and a gateelectrode 622 is connected thereto. That is, the gate electrode 622 isformed by partial extension of the scanning signal line 622 a, and thepicture signal line 620 a and scanning signal line 622 a are disposed inthe form of a matrix.

[0131] Also, as shown in FIG. 9B, the gate electrode (scanning signalelectrode) 622 made of a metal such as, for example, Cr or Al, is formedon a first substrate 607, and a gate insulation film 621 made of, forexample, silicon nitride, etc., is formed so as to cover the gateelectrode 622. A semiconductor film 619 made of, for example,non-crystalline silicon, etc., is formed on the gate electrode 622 viathe gate insulation film 621. The semiconductor film 619 functions as apositive layer of a thin-film transistor (TFT). A drain electrode 620and a source electrode 623, which are made of a metal, for example,molybdenum, etc., are formed so as to overlap a part of a pattern of thesemiconductor 619. The drain electrode 620 and source electrode 623 areformed via a non-crystalline silicon film (not illustrated) into which,for example, an n-type impurity is doped, so that a part thereofoverlaps the semiconductor 619. Furthermore, a protection layer 617 madeof, for example, silicon nitride, is formed so that it covers theentirety of these electrodes and the gate insulation film 621. A lightshielding film 618 is selectively formed on the protection layer 617 sothat it covers the semiconductor film 619, which is a positive layer ofthe TFT. Also, an optical absorption layer 606 is formed on theprotection layer 617, and a reflection layer 605 besides acting as acolor filter consisting of a cholesteric material layer is furtherformed on the protection layer 617. And, the reflection layer 605besides acting as a color filter consisting of the cholesteric materiallayer, optical absorption layer 606, and light shielding layer 618 arecovered by an overcoating layer 616. The overcoating layer 616 is formedof a transparent insulation material that is hardly charged up. A pixelelectrode 615 is formed on the overcoating layer 616, wherein a liquidcrystal orientation film 613 a is coated thereon. The pixel electrode615 is connected to the source electrode 623 via a throughhole 624.

[0132] Further, a transparent substrate 603 is opposed to the firstsubstrate 607 with the liquid crystal layer 604 placed therebetween, andthe transparent substrate 603 is disposed so that it comes forward tothe first substrate 607 in the incident direction of light. A commonelectrode 612 is formed on the surface of the liquid crystal layer 604side of the transparent substrate 603, and an orientation film 613 b iscoated on the liquid crystal layer 604 side as in the pixel electrode615. Also, a wide-band quarter-wavelength plate 602, polarization plate601, and scattering film 608 are formed one after another on the surfaceat the forward side in the light-incident direction of the transparentsubstrate 603, that is, outside the liquid crystal cell, as in thesecond embodiment.

[0133] Orientation films 613 a and 613 b that are, respectively, coatedon the pixel electrode 615 and common electrode 612 may be an adequatecombination of a horizontal orientation film and a perpendicularorientation film on the basis of a liquid crystal mode that is used.Although the liquid crystal mode that is used may be in any form, a modethat does not require rubbing, such as a perpendicular orientation modeand amorphous TN mode, is preferable in view of shortening theproduction process.

[0134] Hereinafter, a description is given of actions of the embodiment,wherein the case of using the perpendicular orientation mode is taken asan example. Also, as in the first embodiment, it is assumed that thereflection layer 605 besides acting as a color filter consisting of acholesteric material layer is right-twisted, and the polarization plate601 and wide-band quarter-wavelength plate 602 are disposed, as shown inFIG. 4, so that the optical axis direction 902 of the quarter-wavelengthplate 602 is inclined clockwise by 45 degrees with respect to thetransmission axis direction 901 of the polarization plate 601, whereinincident light becomes rightward circular-polarized light after havingpassed through the polarization plate 601 and quarter-wavelength plate602. A perpendicular orientation film is coated on the pixel electrode615 and common electrode 612. When no voltage is applied, the liquidcrystal molecules 614 are oriented roughly perpendicular to the firstsubstrate 607 and transparent substrate 603. The incident light 600 ismade into rightward circular-polarized light by passing through thepolarization plate 601 and wide-band quarter-wavelength plate 602, andenters the liquid crystal layer 604. At this time, since the retardationof the light crystal layer 604 is 0, the light is reflected by thereflection plate 605 besides acting as a color filter, and again passesthrough the liquid crystal layer 604, quarter-wavelength plate 602, andpolarization plate 601, wherein the outgoing light 630 scattered by thescattering film 608 creates colors corresponding to the pitches of thereflection plate 605 besides acting as a color filter.

[0135] On the other hand, if voltage is applied to the gate electrode622 to turn on a thin-film transistor (TFT), voltage is applied to thesource electrode 623, and an electric field is induced between the pixelelectrode 615 and the common electrode 612 disposed so as to be opposedthereto. Liquid crystal molecules 614 whose dielectric anisotropy isnegative is shifted down in a direction parallel to the substrate by theelectric field. Thereby, since the retardation of the liquid crystallayer has a specified value, light passes through the reflection plate605 besides acting as a color filter and is absorbed by the opticalabsorption plate 606. Then, the light becomes dark. When the retardationof the liquid crystal layer 604 varies by half a wavelength, all lightthat has passed through the liquid crystal layer 604 is converted toleftward circular-polarized light, and is absorbed by the opticalabsorption layer 606. Therefore, it becomes the darkest. If theretardation (dΔn) that is a product of the refractive index anisotropyΔn of liquid crystal molecules and thickness d of the liquid crystallayer is set to an adequate value, it is possible to control the displayso that it becomes the brightest when no voltage is applied and theretardation of the liquid crystal layer is varied by half a wavelengthwhen appointed voltage is applied, that is, the display becomes thedarkest. Conventionally, brightness is sacrificed in order to secure awide field-of-view angle in a prior art perpendicular orientation mode.However, in the embodiment, it is not necessary to sacrifice thebrightness since a wide coverage is secured by a scattering film 608.Also, a bright display can be secured even when the drive voltage isslight. For example, if a liquid crystal cell of a perpendicularorientation mode having a remarkably large figure such as a retardationdΔn being 670 nm is formed, the retardation dΔn is varied by half awavelength only where the polar angle of liquid crystal moleculesslightly changes, the darkest display can be achieved. At this time,since it is enough to slightly change the polar angle of the liquidcrystal molecules, the application voltage may be slight. However, in aprior art perpendicular orientation mode, if the dΔn is set to such alarge value, the field-of-view angle characteristics are worsened.Therefore, the retardation is suppressed to dΔn=330 nm. Accordingly, itis necessary to significantly change the polar angle of liquid crystalmolecules, whereby the drive voltage becomes large. Further, if aworsening of the field-of-view angle characteristics is taken intoconsideration, such drive cannot be carried out, by which theretardation of liquid crystal is completely changed by half awavelength. Therefore, the brightness is sacrificed. In the presentinvention, since the field-of-view angle characteristics are notworsened even if the retardation (dΔn) of a liquid crystal layer isincreased to any large value, low-voltage drive is enabled, and a brightdisplay is enabled, too. In addition, since a change in the polar angleof liquid crystal molecules may be slight, it is possible to acceleratethe response rate. At this time, although the retardation (dΔn) can bedecreased even if either of the thickness d of liquid crystal cells orthe refractive index anisotropy Δn of the liquid crystal molecules issmall, it is preferable in view of high-speed response that thethickness d of liquid crystal cells is smaller.

[0136] Further, since the light that enters the liquid crystal layer iscircular-polarized light as described above, the display is bright evenif the liquid crystal molecules are shifted down in any direction, it isnot necessary to accurately control the shift-down direction of liquidcrystal molecules as in the prior art perpendicular orientation mode.

[0137] Still further, in a reflection liquid crystal display accordingto the invention, it is not especially necessary to provide the liquidcrystal cell with orientation and division. However, in view of thefield-of-view angle characteristics when being used in a narrowfield-of-view angle, uniformity of the brightness in a display screen,and response rate, it is preferable that the division is smoothlycarried out, depending on liquid crystal materials and elements. In sucha case, the orientation and division may be carried out.

[0138] As regards the orientation and division, if, taking note of thesize and shape of electrodes on the upper and lower substrates, anelectrode on the first substrate 607 is shaped so as to have bettersymmetry, an electrode on the second substrate covers the entirety ofthe upper part of the electrode on the first substrate 607, and theelectrode on the second substrate is wider than the electrode on thefirst substrate 607, no additional process in production is required,wherein the orientation and division can be smoothly carried out.

[0139] Also, by making the shape of the pixel electrode 615 bettersymmetrically and designing the common electrode 612 larger than thepixel electrode 615, an electric field that is produced between both theelectrodes is not perpendicular to the substrates but is made into anoblique electric field facing from the surrounding of the pixelelectrode 615 to the middle thereof. With this electric field, theliquid crystal molecules 614 whose dielectric anisotropy is negative areshifted down symmetrically to the middle of the pixel. Therefore, theorientation direction of the liquid crystal in the pixels is naturallydivided. Thus, the shift-down direction of the liquid crystal molecules614 can be automatically divided without additional processing of theorientation films 613 a and 613 b, wherein the movement of the liquidcrystal is made smooth.

[0140] Further, in a case where the shift-down direction of the liquidcrystal molecules 614 is completely controlled, an optical orientationfilm is used for the orientation films 613 a and 613 b, wherein such anoperation may be carried out, in which polarized light or non-polarizedlight is irradiated obliquely in response to the characteristics of theoptical orientation film. Also, in order to prevent the orientation ofthe liquid crystal from being disordered, a slight amount of monomer maybe doped in liquid crystal, and the liquid crystal may be polymerized inorder to memorize an adequate state of orientation.

[0141] In addition, in the case of the sixth embodiment, since the pixelelectrode 615 is sufficiently apart from the gate line (scanning signalline) 622 a and drain line (picture signal line) 620 a in view of itsstructure, there is almost no case where the orientation of liquidcrystal is disordered due to these electric fields. However, in order toprevent the orientation of liquid crystal from being adverselyinfluenced by the peripheries, a shielding electrode may be provided ateither one or both of the electrodes.

[0142] Hereinafter, a detailed description is given of pixel electrodesused for the purpose of stabilizing the division boundary. FIG. 10Athrough FIG. 10C, FIG. 11A, FIG. 11B, FIG. 12A and FIG. 12B areexemplary plans showing the shapes of the electrodes, which arepreferably used in a reflection liquid crystal display of the presentinvention. In the electrode shapes of the invention, a shape havingbetter symmetry shows a circle or equilateral polygon which has moresides than those of a square as shown in FIG. 10A. If an electrodehaving such better symmetry is used, the electrode at the opposite sidethereof is made wider than the electrode having better symmetry and isformed so as to cover the entirety of the upper part of the electrodehaving better symmetry, an oblique electric field having better symmetrymay be produced between both the substrates when voltage is appliedbetween both the electrodes, and the shift-down direction may be madedouble or more in liquid crystal whose dielectric anisotropy is negativeand perpendicularly oriented, wherein the liquid crystal in pixels maybe oriented and divided. That is, a division boundary is produced at thecenter of a pixel due to an oblique electric field that is naturallyproduced, and liquid crystal is shifted down from the edge of the pixelelectrode to the middle thereof. Since the liquid crystal is naturallyshifted down from respective sides of the pixel electrode to the middleif the shape of the pixel electrode is made symmetrical, the liquidcrystal may be naturally divided. Also, a polygon is not necessarilyequilaterally polygonal, and it may be deformed to some degree.

[0143] Also, in a normal reflection liquid crystal display, the pixelelectrode is rectangular. However, as shown in FIG. 10B, if theelectrode is provided with cuts and is formed so that a plurality ofshapes having better symmetry as shown in FIG. 10A are linked with eachother, orientation and division as described above can be carried out atportions that are shaped so as to have better symmetry. Therefore, it ispossible to obtain effects similar to those of the electrode havingbetter symmetry as a whole.

[0144] In order to further secure orientation and division, as shown inFIG. 11A, in a pixel electrode having better symmetry as shown in FIG.10A, an electrode may be formed in a form that cuts are formed atequidistant positions on the circumference or at the corners of anequilateral polygon, and, as shown in FIG. 11B, projections protrudingoutward are provided at equidistant positions on the circumference of apixel electrode having better symmetry as shown in FIG. 10A, or cornersof an equilateral polygon, and, as shown in FIG. 12A, in the pixelelectrode having better symmetry as shown in FIG. 10A, a circle isdivided into a plurality of areas by segments passing from the centerthereof to equidistant positions on the circumference of the circle, oran equilateral polygon is divided into a plurality of areas by segmentspassing from the center thereof to the corners thereof, wherein a partof these divided areas is removed, wherein an electrode having no pixelelectrode may be formed. Still further, as shown in FIG. 12B, anelectrode having better symmetry as shown in FIG. 10A is divided into aplurality of areas as in FIG. 12A, and a recess may be provided at apart of the divided areas. Also, these shapes may be combined.

[0145] In the case of a structure in which a recess is provided, it ispossible to form a recess deeply without making the process ofexcavating an overcoat layer complicated, wherein the boundary may befurther securely fixed. In addition, in the case of perpendicularorientation, when voltage is applied, the orientation may be stabilizedlike an eddy. However, the orientation can be further stabilized byfeeding a chiral agent in order to make the response rate faster. Also,cuts at a part of said pixel or recess may be established to be like aneddy in the pixel.

[0146] Next, a description is given of a method for producing areflection liquid crystal display according to the six embodiment of theinvention.

[0147] First, by repeating a film forming process and lithographyprocess, a substrate having an amorphous silicon thin-film transistorarray (TFT) is formed on a glass substrate. The TFT may be composed of,for example, a gate chrome layer, silicon nitride-gate insulation layer,amorphous silicon-semiconductor layer and drain-source molybdenum layerin the order from the substrate side. Next, a protection film 617 madeof, for example, SiNx, etc., is formed on the gate insulation film 621so that it covers the drain electrode 620, source electrode 623 andsemiconductor film 619. Thus, a substrate 607 is formed.

[0148] Next, an optical absorbing layer 606 is formed on the protectionlayer. A resin including a black dye or pigment may be used as anoptical absorbing layer 606. Also, the optical absorbing layer 606 maybe formed by using a metal. Next, a reflection layer 605 besides actingas a color filter consisting of a cholesteric material layer is formed.Such a cholesteric material layer may be formed of a cyloxane-basedcompound, whose chiral pitch is adjusted to an appointed color, asdescribed in, for example, R. Mauer, D. Andrejewski, F -H. Kreuzer, A.Miller, SID90DIGEST pages 110-112 (1990), or a liquid crystal materialhaving a photosensitive group as described in Liquid Crystals, Vol.No.18, page 319 (1995), whose chiral pitch is adjusted to an appointedcolor as well.

[0149] In order to form a reflection layer 605 besides acting as a colorfilter, first, an orientation film is coated on the protection layer 617and is heated for burning. Further, as necessary, rubbing or processingfor optical orientation is carried out. Next, a cyloxane-based compoundwhose chiral pitch has been adequately adjusted or a liquid crystalmaterial having a photosensitive group whose chiral pitch has beenadjusted to an appointed color is coated at an appointed thickness byusing a laser blade, etc. After that, it is exposed to light by using aphoto mask so that light is selectively irradiated onto an appointedarea, that is, a pixel area disposed in the form of a matrix. After theexposure to light, the substrate is developed by using an appointedorganic solvent, wherein an appointed pattern is formed. These processesare repeated three times equivalent to the liquid crystal layer havingchiral pitches of three colors, for example, red, blue and green, and acolor layer is left for the respective pixels, whereby a reflectionlayer 605 besides acting as a color filter consisting of a cholestericmaterial layer can be formed. At this time, if the chiral agent is madeinto, for example, a right-twisted chiral agent, the right-twistedcholesteric material layer can be formed.

[0150] Next, an overcoat layer 616 made of a transparent insulationmaterial is formed on the reflection layer 605 besides acting as a colorfilter. The overcoat layer 616 may be made of, for example, a thermallyhardening resin such as acrylate resin. Also, an optically hardeningtransparent resin may be used as the overcoat layer 616.

[0151] Finally, a throughhole 624 is formed, and a pixel electrode 615that is connected to the source electrode 623 via the throughhole 624 isformed on the overcoat layer 616. If the pixel electrode 615 is formedto be a circle or equilateral polygon which has more sides than those ofa square and has better symmetry, as described above, the divisionboundary of the liquid crystal layer 604 can be stabilized.

[0152] On the other hand, for example, ITO, etc., is spattered andpatterned on the entire surface of the substrate made of, for example,transparent glass in order to form a common electrode 612, wherein atransparent substrate 603 that will become an opposed substrate of thefirst substrate 607 is formed. And, perpendicular orientation films 613a and 613 b are, respectively, coated on the pixel electrode 615 andcommon electrode 613 of these substrates, and heated for drying.Further, a sealing agent is coated around these substrates. After aspacer agent of, for example, 4 μm of diameter, is sprayed, the sealingagent is hardened by heating, and nematic liquid crystal whosedielectric anisotropy is negative is poured, wherein the pouring port issealed by an optically hardening resin.

[0153] Further, a wide-band quarter-wavelength plate 602, a polarizationplate 601 on the wide-band quarter-wavelength plate, and scattering film608 are formed on the side opposed to the side where the first substrate607 of the transparent substrate 603 is disposed. At this time, theoptical axis of the quarter-wavelength plate 602 is set so that theoptical axis of the quarter-wavelength plate 602 and transmission axisof the polarization plate 601 come to an angle of 45 degrees clockwiseor counterclockwise when being measured from the transmission axis ofthe polarization plate 601.

[0154] A panel of normally white mode, which is thus produced, can bringabout excellent field-of-view angle characteristics in which no changein colors is caused to occur due to the angle, and the area of highcontrast is made remarkably wide. Further, in adhering the upper andlower substrates together, there is no need to carry out alignment, andthere is completely no problem even if the pixel size is decreased. Inaddition, the intensity of the reflection light is brighter than inprior arts, wherein no problem in parallax occurs. Also, in the casewhere a scattering film 608 is removed, a color tint changes in thepolar angle direction exceeding ±20 degrees, and it is possible tochange over a narrow field-of-view angle and a wide field-of-view angleby attaching and detaching the scattering film 608.

[0155] With the present invention, a remarkable effect is brought aboutespecially in the case of an active matrix liquid crystal display inwhich a switching element such as a TFT is used. That is, in the case ofan active matrix liquid crystal display, in liquid crystal displayelements in which a normal TN mode is used, a micro-processing step suchas a photo-resist processing, etc., is required only for one substratein which active elements are produced. Usually, no micro-processing stepis required in the other substrate that is called a common electrode,wherein an electrode is formed on the entirety of the surface thereof.Where an attempt is made to orient and divide liquid crystal in pixels,the photo-resist processing is increased in a prior art technology. Anincrease in the photo-resist processing results in an increase in loadin the production facilities, and a lowering of yield. Therefore, it ispreferable that such a micro-processing step such as a photo-resistprocessing is not required. Therefore, according to the embodiment, itis possible to orient and divide liquid crystal in pixels without anyincrease in the photo-resist processing.

[0156] In addition, especially, in the case of an active matrix liquidcrystal display, there may be a case where an unnecessary disclinationline enters the pixel electrode portion due to influences of a lateralelectric field from the scanning signal electrode and picture signalelectrode. Such a problem can be solved by increasing the distancebetween the scanning signal electrode, picture signal electrode andpixel electrode. However, an increase in the distance is not preferablein view of a ratio of opening where the pixel size is made small.Another method to solve this problem is to dispose a part of the pixelelectrode or a shielding electrode on the upper part of at least eitherone of the scanning signal electrode or picture signal electrode. Thatis, the ratio of opening is lowered by shielding all the scanning signalelectrode and picture signal electrode with the pixel electrode.Therefore, by disposing a pixel electrode or a shielding electrode onthe upper part of at least either one of the scanning signal electrodeor picture signal electrode, it is possible to prevent the ratio ofopening from being lowered. In this case, when selecting an arrangement,the most favorable arrangement can be selected by taking intoconsideration the shape of a pixel, arrangement of the scanning signalelectrode and picture signal electrode, and a sequence of forming theshielding electrode.

[0157] Still further, in the present invention, a pixel electrode isdisposed between the reflection layer besides acting as a color filterand the liquid crystal layer, whereby since no alignment is requiredbetween the reflection layer besides acting as a color filter and thepixel electrode, the overlapping accuracy of the upper and lowersubstrates can be remarkably relieved. It is completely impossible toobtain such a remarkable effect in a technology in which an opening isprovided at the common electrode. Also, by disposing a pixel electrodebetween the reflection layer besides acting as a color filter and theliquid crystal layer, it is possible to remarkably relieve theinfluences due to a lateral electric field from the scanning signalelectrode and picture signal electrode.

[0158] Next, a description is given of a seventh embodiment of theinvention. FIG. 13A is a plan view showing a reflection liquid crystaldisplay according to the seventh embodiment of the invention. FIG. 13Bis a sectional view taken along the line B-B of FIG. 13A. FIG. 13A andFIG. 13B show a detailed structure in which liquid crystal is driven byan active element. A point at which the seventh embodiment differs fromthe sixth embodiment resides in that a liquid crystal layer isfour-divided TN liquid crystal instead of perpendicularly orientedliquid crystal. As shown in FIG. 13A and FIG. 13B, the shape of a pixelelectrode 715 in the embodiment is square. Other construction is similarto that of the sixth embodiment.

[0159] The embodiment shown in FIG. 13A and FIG. 13B shows an example inwhich the dielectric anisotropy of a liquid crystal layer 704 isnegative and the liquid crystal is twisted-nematically oriented.Processes for rubbing and optical orientation are provided for a firstsubstrate 707 and a transparent substrate 703, opposed thereto, which isdisposed so that it comes forward to the first substrate 707 in thelight-incident direction, wherein the direction of orientation of liquidcrystal is regulated.

[0160] In the invention, an attempt is made to produce areas in whichthe rise directions of liquid crystal molecules 714 are different fromeach other, by using an oblique electric field. At this time, if theliquid crystal molecules 714 are provided with a pre-tilt angle, theliquid crystal molecules 714 are caused to rise in that direction,resulting in removal of the effect of an oblique electric field. As aresult, no orientation and division is enabled. Therefore, in this case,it is preferable that the pre-tilt angle of the liquid crystal layer 704is as small as possible, preferably 1 degree or less, further preferablyzero. Such orientation can be easily obtained by using orientation films713 a and 713 b that are oriented in a direction orthogonal to therubbing direction, or irradiating polarized light to optical orientationfilms from the normal direction of a substrate. Also, no chiral agent isprovided. In such a state, if voltage is applied between the upper andlower electrodes of the liquid crystal layer 704, that is, the commonelectrode 712 and pixel electrode 715, an oblique electric field can beproduced, as described above, with better symmetry by thecharacteristics that the upper and lower electrodes have, wherein theliquid crystal is naturally divided into areas whose twisting directionand rise direction differ. There is a possibility that bothright-twisting and left-twisting occur in respective parts of a pixel.However, in the case where, for example, a square pixel electrode 715 isformed as in the embodiment, an orientation direction 726 of a liquidcrystal molecules 714 a at the boundary of the transparent substrate 703becomes, as shown in FIG. 13A, a position twisted by 90 degrees from anorientation direction 725 of the liquid crystal molecules at theboundary of the first substrate 707 by the oblique electric field. Thisis because at respective areas of a pixel, twisting in one direction ispreferentially produced, and a state of orientation shown in FIG. 13A isautomatically produced. That is, due to the effects of the electrode onthe first substrate 707 being shaped so as to have better symmetry, thecommon electrode 712 on the transparent substrate 703 covering theentirety of the upper part f the pixel electrode 615 on the firstsubstrate 707, and the common electrode 712 being wider than the pixelelectrode 715, a pixel can be naturally divided with better symmetry inthe case of the twisted-nematic orientation.

[0161] In order to further secure the division position, as shown inFIG. 11A, FIG. 11B, FIG. 12A and FIG. 12B, there are several methods, inwhich projections that protrude at the corners of the pixel electrode oroutward at the surrounding thereof are provided, or cuts are provided ata part of the pixel electrode, or the pixel electrode is divided into aplurality of areas, and a portion having no pixel electrode is providedalong the division boundary by removing a part of the areas. This iscompletely the same as in the example in which the dielectric anisotropyis negative.

[0162] The above example is based on a case where no chiral agent isprovided. However, a chiral agent may be included. In this case, atwo-division TN is brought about, in which only the rise directiondiffers, wherein it is possible to carry out orientation and division inthe liquid crystal in a pixel.

[0163] Next, a description is given of actions of the embodiment. Theretardation (dΔn) of a liquid crystal cell is adjusted so that, when novoltage is applied, the dΔn becomes equivalent to half a wavelength,that is, the phase difference becomes π. As in the sixth embodiment, areflection layer 705 besides acting as a color filter consisting of acholesteric material layer is right-twisted. As regards arrangement of apolarization plate 701 and a wide-band quarter-wavelength plate 702, adescription is given of a case where the polarization plate 701 and thewide-band quarter-wavelength plate 702 are, as shown in FIG. 4, disposedso that the optical axis direction 902 of the quarter-wavelength plate702 is inclined by 45 degrees clockwise with respect to the transmissionaxis direction 901 of the polarization plate 701, and incident light 700is made into rightward circular-polarized light after it has passedthrough the polarization plate 701 and quarter-wavelength plate 702. Ina state where no voltage is applied, as in the sixth embodiment, theincident light 700 is made into rightward circular-polarized light, andis converted to leftward circular-polarized light as it passes throughthe liquid crystal layer 704. Then, the light passes through thereflection layer 705 besides acting as a color filter consisting of acholesteric material layer, and is absorbed by an optical absorbinglayer 706. Therefore, the pixel is displayed to be black.

[0164] On the other hand, if a thin-film transistor (TFT) is turned onwith voltage applied to a gate electrode 722, voltage is applied onto asource electrode 723, wherein an electric field is induced between thepixel electrode 715 and a common electrode 712 disposed so as to beopposed thereto. By the electric field, liquid crystal molecules 714whose dielectric anisotropy is positive are caused to rise in adirection perpendicular to the substrate, wherein the retardation (dΔn)of liquid crystal becomes almost zero, the reflection light passesthrough the polarization plate 702, is scattered by the scattering plate708, is made into radiation light 730 having an adequate field-of-viewangle, and is observed by an observer's eyes.

[0165] Also, in order to further securely perform orientation anddivision, methods for polymerizing liquid crystal or altering the shapeof the pixel electrode 715 are the same as those in the sixthembodiment. Also, a narrow field-of-view angle and a wide field-of-viewangle can be easily changed over by attaching and detaching a scatteringfilm 708 or providing or not providing a scattering property in amacromolecular dispersion liquid crystal layer 608. This is also thesame as that of the sixth embodiment.

[0166] Next, a description is given of an eighth embodiment of theinvention. FIG. 14A is a sectional view showing a reflection liquidcrystal display according to the eighth embodiment of the invention, andFIG. 14B is a plan view showing a liquid crystal layer of the presentembodiment. A point at which the present embodiment differs from theseventh embodiment resides in that a liquid crystal layer 804 is made ofhomogeneous liquid crystal (having no chiral agent) as shown in FIG. 14Binstead of perpendicularly oriented liquid crystal. As shown in FIG.14A, constructions other than the liquid crystal layer 804 are the sameas those of the seventh embodiment.

[0167] In the embodiment, a horizontally oriented film is employedinstead of a perpendicularly oriented film. There is no need to carryout any rubbing as in the perpendicularly oriented liquid crystal. ONand OFF of reflection light are made inverse of the case ofperpendicular orientation when the dielectric anisotropy of liquidcrystal is positive and no voltage is applied. That is, when no voltageis applied, the retardation (dΔn) of the liquid crystal layer is set tohalf a wavelength (phase difference is set to π). At this time, incidentlight 800 is absorbed by an optical absorbing layer 806 in themechanism, which is similar to that of the seventh embodiment, and it isdisplayed to be black.

[0168] On the other hand, completely as in the seventh embodiment, ifvoltage is applied to a gate electrode 822 and a thin-film transistor(TFT) is turned on, voltage is applied to a source electrode 823, and anelectric field is induced between a pixel electrode 815, which is formedon the surface at the rearward side in the light-incident direction of aliquid crystal layer 804, and a common electrode 812, which is formed onthe surface at the forward side in the light-incident direction of theliquid crystal layer 804 so that it is opposed to the pixel electrode815. By the electric field, a liquid crystal molecule 814 whosedielectric anisotropy is positive is caused to rise in a directionperpendicular to the substrate, wherein the retardation of the liquidcrystal becomes almost 0, the reflection light passes through apolarization plate 801, is scattered by a scattering plate 808, andradiation light 830 enters an observer's eyes with an adequatefield-of-view angle. At this time, since no orientation process isprovided for orientation films 813 a and 813 b, the direction alongwhich liquid crystal is caused to rise is random. However, since lightreflected by the liquid crystal layer 804 that is displayed to be brightis circular-polarized light, brightness occurs regardless of thedirection along which the liquid crystal rises, wherein a bright displayis enabled. Also, by controlling the rise angle of liquid crystal byvoltage application, it is possible to display intermediate colors.

[0169] In this case, as in the sixth and seventh embodiments, in view ofthe field-of-view angle characteristics when being used in a narrowfield-of-view angle, uniformity of the brightness in a display screen,and response rate, it is preferable that the division is smoothlycarried out, depending on liquid crystal materials and elements. In sucha case, completely as in the sixth and seventh embodiments, by using thepixel electrode 815 having higher or better symmetry and designing thecommon electrode 812 so as to become larger than the pixel electrode815, the orientation and division can be smoothly carried out. In orderto more reliably carry out the division, at least either one of a drainelectrode 820 or a gate electrode 822 is provided with a shieldingelectrode or is polymerized, a part of the pixel is provided with a cut,or a part of the pixel is removed, or a recess is provided at a part ofthe pixel electrode 815. Such measures may be carried out completely asin the sixth embodiment.

[0170] Further, in a case where it is recommended that the orientationdirection of liquid crystal be divided into two, the upper and lowersubstrates are processed by rubbing and optical orientation, and theorientation direction of the liquid crystal may be regulated. FIG. 15Ais a sectional view showing a reflection liquid crystal display in thecase where the orientation direction of liquid crystal is regulated, andFIG. 15B is a plan view showing a liquid crystal layer of the reflectionliquid crystal display of FIG. 15A. As shown in FIG. 15B, by rubbing andoptical orientation, the orientation direction 826 a of the liquidcrystal molecule 814 at the boundary of the transparent substrate 803 isthe same as, and is parallel to the orientation direction 825 b of theliquid crystal molecule 814 at the boundary of the first substrate 807.Thus, since the orientation direction of liquid crystal at the boundaryof substrates is regulated, two types of domains whose rise directionsare different from each other are produced.

[0171] In addition, when providing a part of a pixel with a cut,removing a part of the pixel, or providing a part of the pixel electrodewith a recess, it is better that an orientation process such as rubbing,etc., which determines the azimuth angle direction is carried out in thedirection along which the division can be smoothly carried out.

[0172] In the case of homogeneous orientation, especially, in order tostabilize the boundary area, it is recommended that a recess is providedat the middle. Next, a description is given of the case where a recessis provided. FIG. 16A is a sectional view showing a reflection liquidcrystal display having a pixel electrode in which a recess is formed,and FIG. 16B is a plan view showing a liquid crystal layer of thereflection liquid crystal display of FIG. 16A. As shown in FIG. 16B, itis shown that a recess 827 is provided in a direction orthogonal to theorientation direction at the middle portion of the pixel electrode 815.In FIG. 16B, 825b and 826 b, respectively, denote the orientationdirections of liquid crystal molecules 814 at the boundary of the firstsubstrate 807 and at the boundary of the transparent substrate 803.Also, in this case, it is recommended that the pre-tilt angle is almostzero. Such orientation can be easily obtained by irradiating polarizedlight from the normal direction of the substrates onto an orientationfilm, which is oriented in the perpendicular direction from the rubbingdirection, and an optical orientation film. Also, no chiral agent isprovided. In such a state, if voltage is applied between the upper andlower electrodes of the liquid crystal layer 804, an oblique electricfield is produced with better symmetry by the shape characteristics ofthe upper and lower electrode 815 and common electrode 812. Since theorientation direction of liquid crystal at the boundary of bothsubstrates is regulated, two types of domains whose rise directions aredifferent from each other are produced. In particular, in order tostabilize the boundary areas, in parallel to a side of the pixelelectrode 815, a part of an electrode for pixel display is provided witha cut, a part of the electrode is removed or is provided with a recess.It is better that the initial orientation of liquid crystal is set so asto become perpendicular to the above measures.

EXAMPLES

[0173] Next, a description is given of the characteristics of areflection liquid crystal display according to the examples of theinvention, and their effects will also be described.

Example 1

[0174] A reflection liquid crystal display, which is similar to thesixth embodiment shown in FIG. 8, was fabricated. First, a film-formingprocess and a lithography process were repeated, wherein a gate chromelayer, a silicon nitride-gate insulation layer, a amorphoussilicon-semiconductor layer, and a drain-source molybdenum layer werelaminated from a substrate side. A substrate having an amorphous siliconthin-film transistor array (TFT) was prepared. Next, a protection layermade of SiNx was formed on the gate insulation film so that it coversthe drain electrode, source electrode and semiconductor film. Next, anoptical absorbing layer and a reflection layer besides acting as a colorfilter consisting of a cholesteric material layer were formed on theprotection layer. Further, an orientation film was coated on theprotection layer and was heated for burning. In addition, processes ofrubbing and optical orientation were carried out. Next, a cyloxane-basedcompound whose chiral pitch was adequately adjusted was coated atappointed thickness by using a laser blade. Next, after the substratewas exposed to light by using a photo mask so that light is irradiatedonto an appointed area, that is, is selectively irradiated onto pixelareas disposed in the form of a matrix, it was developed by using anappointed organic solvent, wherein an appointed pattern was formed.These processes were repeated three times on the liquid crystal havingchiral pitches equivalent to three colors (red, blue and green), whereina reflection layer besides acting as a color filter consisting of acholesteric liquid crystal was formed by causing respective color layersto remain per pixel. At this time, a right-twisted chiral agent wasused. Next, an overcoat layer made of an acrylate resin that is atransparent insulation material was formed on the reflection layerbesides acting as a color filter. Finally, a throughhole was formed, anda pixel electrode having a rectangular shape, which is connected to thesource electrode via the throughhole was formed on the overcoat layer.

[0175] A glass substrate having its entire surface spattered with ITOwas prepared as an opposite substrate that is the second substrate, anda perpendicularly oriented film (Nissan Chemical Corp., SE1211) wascoated on both the substrates. Then, they were heated for one hour at atemperature of 180° C. for drying. A sealing agent was coated around thesubstrates. After a spacer agent of 4 μm dia., was sprayed, the sealingagent was hardened by heating, and nematic liquid crystal (Merck,MLC6608) whose dielectric isotropy is negative was poured, and itspouring port was sealed with an optically hardening resin. A wide-bandquarter-wavelength plate was formed outside the opposite substrate, andfurther a polarization plate was disposed so that the optical axisdirection of the quarter-wavelength plate is inclined by 45 degreesclockwise with respect to the transmission axis direction of thepolarization plate. A diffusion sheet having a scattering property wasfurther provided thereon.

[0176] The field-of-view angle characteristics of a panel of a normallywhite mode, which had been thus obtained were measured. Excellentfield-of-view angle characteristics, in which no change in color tintresulting from a degree of angle was recognized, having a remarkablywide high contrast area were obtained. Also, no alignment of thesubstrates was required when adhering the upper and lower substratestogether, and it was found that there is no problem even if the size ofa pixel is made smaller. In addition, the intensity of reflection lightwas brighter than that of prior arts, wherein it was found that anexcellent capacity had been obtained with respect to the brightness.Further, it was found that no problem resides in relation to parallax.

[0177] Where the field-of-view angle characteristics were measured withthe scattering sheet removed, the color tint was made different in thepolar angle direction exceeding ±20 degrees, and a normal picture imagecould be recognized in only a narrow field-of-view angle.

Example 2

[0178] Another reflection liquid crystal display was formed in a statewhere the scattering sheet is changed to a macromolecular dispersionliquid crystal layer having ITO electrode formed on both sides, and allother constructions are the same as those of Example 1. Then, thefield-of-view angle characteristics were measured. As a result,excellent field-of-view angle characteristics having a remarkably wideand high contrast area, in which no change in color tint is provided atan angle of observation when no voltage is applied, were obtained. Also,the brightness is the same as that of Example 1, wherein bright displaycould be obtained.

[0179] Next, where voltage was applied onto the macromoleculardispersion liquid crystal layer, a picture image could be recognized inonly a narrow field-of-view angle as in Example 1.

Example 3

[0180] A TFT substrate having a reflection layer besides acting as acolor filter consisting of a cholesteric material layer was preparedcompletely as in the case of Example 1. A glass substrate having ITOspattered on its entire surface was prepared as an opposite substratecompletely as in the case of Example 1. A horizontally oriented film(JSR Corp., AL1051) was coated on both the substrates, and thesubstrates were heated for one hour at a temperature of 180° C. fordrying. Also, by adequately leaving a reflection layer, besides actingas a color filter, and an overcoat layer on the gate wiring and drainwiring on the TFT substrate instead of spraying a spacer agent, postswhose sizes were 10 μm long, 20 μm wide, and 2 μm high were formed. Asealing agent was coated around the substrates. The upper and lowersubstrates are adhered to each other, wherein the sealing agent washardened by heating, and nematic liquid crystal (Merck, TL-213) whosedielectric anisotropy was positive was poured without mixing any chiralagent. The pouring port was sealed by an optically hardening resin.

[0181] Completely as in Example 1, a wide-band quarter-wavelength plateand a polarization plate were formed outside the opposite substrate. Atthis time, the optical axis was set so as to establish 45 degreesclockwise when being measured from the transmission axis of thepolarization plate. A diffusion sheet having a scattering property wasinstalled thereon.

[0182] The field-of-view angle characteristics of a panel of a normallyblack mode, which had been thus obtained were measured. Completely as inExample 1, excellent field-of-view angle characteristics, in which nochange in color tint resulting from a degree of angle of observation wasrecognized, having a remarkably wide high contrast area was obtained.Also, the intensity of transmission light was brighter than that ofprior arts, completely as in Example 1, wherein it was found that anexcellent capacity had been obtained with respect to the brightness.

[0183] Also, as in Example 1, where the field-of-view anglecharacteristics were measured with the scattering sheet removed, thecolor tint was made different in the polar angle direction exceeding ±20degrees, and a normal picture image could be recognized in only a narrowfield-of-view angle.

Example 4

[0184] A TFT substrate was prepared, in which the shape of a pixelelectrode is shaped so that three squares are lined up one afteranother. Also, a liquid crystal material having a photosensitive groupwas used as cholesteric liquid crystal. All other constructions are thesame as those in Example 1, wherein vertical liquid crystal was poured,and after the pouring port was sealed, a quarter-wavelength plate,polarization plate, and a diffusion sheet were adhered to the oppositesubstrate side.

[0185] The field-of-view angle characteristics of a panel of a normallywhite mode , which had been thus obtained were measured. Completely asin Example 1, excellent field-of-view angle characteristics, in which nochange in color tint resulting from a degree of angle was recognized,having a remarkably wide high contrast area were obtained. Also, theresponse rate was made faster than that in Example 1.

[0186] Next, also, as in Example 1, where the field-of-view anglecharacteristics were measured with the scattering sheet removed,field-of-view angle characteristics having excellent uniformity on theentire panel were obtained in comparison with Example 1. Also, as in thecase of Example 1, a normal picture image could be recognized in only anarrow field-of-view angle, in comparison with the case where ascattering film is provided.

Example 5

[0187] Completely as in the case of Example 1, a TFT substrate having areflection layer besides acting as a color filter consisting of acholesteric material layer was prepared. Completely as in the case ofExample 1, a glass substrate having ITO spattered on its entire surfacewas prepared as an opposite substrate. A horizontally oriented film (JSRCorp., AL1051) was coated on both the substrates, and the substrateswere heated at a temperature of 180° C. for one hour for drying. As inExample 1, a sealing agent was coated around the substrates, and after aspacer agent of 6 μm of diameter was sprayed, the sealing agent washardened by heating, wherein nematic liquid crystal (Merck Corp.,ZLI-4792) whose dielectric anisotropy is positive and chiral pitch isadjusted to 6 μm (right-twisted) was poured, and the pouring port wassealed by an optically hardening resin.

[0188] Completely as in the case of Example 1, a wide-bandquarter-wavelength plate and a polarization plate were set outside theopposite substrate in order, so that, with respect to the optical axisof the quarter-wavelength plate and transmission axis of thepolarization plate, the optical axis of the quarter-wavelength plate ispositioned at 45 degrees clockwise when being measured from thetransmission axis of the polarization plate. A diffusion sheet having ascattering property was provided thereon.

[0189] The field-of-view angle characteristics of a panel of a normallywhite mode, which had been thus obtained were measured. Excellentfield-of-view angle characteristics, in which no change in color tintresulting from a degree of angle was recognized in an angle ofobservation, having a remarkably wide high contrast area were obtained.Also, with respect to the brightness, as in Embodiment 1, it was foundthat an excellent capacity could be obtained.

[0190] Also, where the field-of-view angle characteristics were measuredwith the scattering sheet removed, the color tint became completelydifferent in the polar angle direction exceeding ±20 degrees as in thecase of Embodiment 1, and a normal picture image could be recognized inonly a narrow field-of-view angle.

Example 6

[0191] Completely as in the case of Example 5, a TFT substrate having areflection layer besides acting as a color filter consisting of acholesteric material layer was prepared. A glass substrate having ITOspattered on its entire surface was prepared as an opposite substrate. Ahorizontally oriented film (JSR Corp., AL1051) was coated on both thesubstrates, and the substrates were heated at a temperature of 180° C.for one hour for drying. Herein, rubbing was carried out, as inconventional TN, with its rubbing direction inclined by 45 degrees fromthe side of the panel and turned by 90 degrees toward the upper andlower substrates, and as in Example 5, a sealing agent was coated aroundthe substrates. After a spacer agent of 2 μm of diameter was sprayed,the sealing agent was hardened by heating. A nematic liquid crystal(Merck Corp., TL-213) whose dielectric anisotropy is positive and chiralpitch is adjusted to be 30 μm (right-twisted) was poured, and thepouring port was sealed by an optically hardening resin. Also, therubbing direction was set so that a 90-degree twisted direction bringsabout normal orientation.

[0192] Completely as in Example 5, a wide-band quarter-wavelength plateand a polarization plate were formed outside the opposite substrate. Atthis time, they were set so that the optical axis of thequarter-wavelength plate is turned by 45 degrees clockwise when beingmeasured from the transmission axis of the polarization plate. Adiffusion sheet having a scattering property was provided thereon.

[0193] The field-of-view angle characteristics of a panel of a normallyblack mode, which had been thus obtained were measured. Excellentfield-of-view angle characteristics, in which no change in color tintresulting from a degree of angle of observation was recognized, having aremarkably wide high contrast area were obtained. Also, as in Example 1,excellent performance could be obtained with respect to the brightness.Further, the response rate was also excellent, being reflected by anarrow gap.

[0194] Also, where the field-of-view angle characteristics were measuredwith the scattering sheet removed, a change in color tint occurred at 15degrees in the downward direction of the panel, and the field-of-viewangle became remarkably narrow.

Example 7

[0195] By a method that is similar to that in Example 1, a TFT substratein which the shape of a pixel electrode is made square was prepared.Completely as in the case of Example 1, a glass substrate having ITOspattered on its entire surface was prepared as an opposite substrate. Ahorizontally oriented film (JSR Corp., JALS-428) was coated on both thesubstrates, and the substrates were heated at a temperature of 180° C.for one hour for drying. Herein, as in Embodiment 6, rubbing was carriedout with its rubbing direction inclined by 45 degrees from the side ofthe panel and turned by 90 degrees toward the upper and lowersubstrates, and as in Example 6, a sealing agent was coated around thesubstrates. After a spacer agent of 6 μm dia., was sprayed, the sealingagent was hardened by heating. A nematic liquid crystal (Merck Corp.,ZLI-4792) whose dielectric anisotropy is positive and chiral agent isremoved was poured, and the pouring port was sealed by an opticallyhardening resin. Thereby, when voltage was applied, one pixel isnaturally divided into four areas, whose rise directions and twistingdirections are different from each other, by an oblique electric field.

[0196] Completely as in Example 1, a wide-band quarter-wavelength platewas formed outside the opposite substrate, and further a polarizationplate was disposed so that the optical axis direction of thequarter-wavelength plate could be inclined by 45 degrees clockwise withrespect to the transmission axis direction of the polarization plate. Adiffusion sheet having a scattering property was provided thereon.

[0197] Where the field-of-view angle characteristics of a panel of anormally black mode, which had been thus obtained were measured,excellent field-of-view angle characteristics free from any invertedgraduation, in which the area of high contrast is remarkably wide, couldbe obtained. Also, as in Example 1, it was found that the performanceregarding brightness was excellent.

[0198] In addition, where the field-of-view angle characteristics weremeasured with the scattering sheet removed, the color tint was madedifferent in the polar angle direction exceeding ±20 degrees as in thecase of Embodiment 1, and a normal picture image could be recognized inonly a narrow field-of-view angle.

Example 8

[0199] Completely as in Example 1, a TFT substrate in which the shape ofa pixel electrode is made square, and a recess is formed by digging theovercoat layer at the middle part of the pixel as in the eighthembodiment shown in FIG. 12A and FIG. 12B, was prepared. Completely asin the case of Example 1, a glass substrate having ITO spattered on itsentire surface was prepared as an opposite substrate. In addition, as inExample 7, a horizontally oriented film (JSR Corp., JALS-428) was coatedon both the substrates, and the substrates were heated at a temperatureof 180° C. for one hour for drying. Rubbing was performed on thesubstrates along the long side of the recess. In the oriented film, theliquid crystal was oriented in the rubbing direction and perpendiculardirection, that is, directions 825 b and 826 b in FIG. 12B, and thepre-tilt angle was almost zero degrees. As in Example 3, by adequatelyleaving a reflection layer, besides acting as a color filter, and anovercoat layer on the gate wiring and drain wiring instead of spraying aspacer agent, posts whose sizes were 10 μm long, 20 μm wide, and 2 μmhigh were formed. A sealing agent was coated around the substrates. Theupper and lower substrates are adhered to each other, wherein thesealing agent was hardened by heating, and nematic liquid crystal(Merck, TL-213) whose dielectric anisotropy was positive was pouredwithout mixing any chiral agent. The pouring port was sealed by anoptically hardening resin. As in Example 3, a wide-bandquarter-wavelength plate and a polarization plate were set outside theopposite substrate in order, so that, with respect to the optical axisof the quarter-wavelength plate and transmission axis of thepolarization plate, the optical axis of the quarter-wavelength plate wasset so as to establish 45 degrees clockwise when being measured from thetransmission axis of the polarization plate. A diffusion sheet having ascattering property was installed thereon.

[0200] The field-of-view angle characteristics of a panel of a normallyblack mode, which had been thus obtained were measured. Completely as inExample 1, excellent field-of-view angle characteristics, in which nochange in color tint resulting from a degree of angle of observation wasrecognized, having a remarkably wide high contrast area were obtained.Also, the intensity of transmission light was bright in comparison withprior arts completely as in Example 1, wherein it was found that anexcellent capacity has been obtained with respect to the brightness.

[0201] Also, as in Example 1, where the field-of-view anglecharacteristics were measured with the scattering sheet removed, thecolor tint was made different in the polar angle direction exceeding ±20degrees, and a normal picture image could be recognized in only a narrowfield-of-view angle.

Example 9

[0202] A wide-band quarter-wavelength plate was formed outside theopposite substrate of liquid crystal cells having a reflection layer,besides acting as a color filter consisting of a cholesteric materiallayer, which was prepared as in Example 1. Further, the polarizationplate was disposed so that the optical axis direction of thequarter-wavelength plate is inclined by 45 degrees clockwise withrespect to the transmission axis direction of the polarization plate.Still further, a diffusion sheet having a scattering property wasprovided thereon. The twisting of the cholesteric material layer isreverse of that of the reflection layer besides acting as a color filterconsisting of a cholesteric material layer. That is, a left twisting wasemployed.

[0203] Then, the field-of-view angle characteristics were measured. Theresults, which are the same as those of Example 1, were obtained. If ascattering film is provided, the field-of-view angle is wide, and if ascattering sheet is removed, the field-of-view angle is made narrow.Also, the brightness was higher than prior art liquid crystal elements.

Example 10

[0204] By a method that is similar to that of Example 1, a reflectionlayer besides acting as a color filter consisting of a cholestericmaterial layer, and a three-prime-color cholesteric material layer wereformed inside the liquid crystal cell. Example 10 is different fromExample 9 in that a three-prime-color cholesteric material layer isformed inside the liquid crystal cell. That is, the three-prime-colorcholesteric material layer was prepared on a glass substrate of theopposite substrate by a method that is similar to that of Example 1.After an overcoat layer was coated, ITO was formed. The glass substratewas used as the opposite substrate. As in Example 1, where a liquidcrystal panel was prepared, and the field-of-view angle characteristicsof the panel that had been thus obtained were measured, excellentfield-of-view angle characteristics, in which no change in color tint isprovided as in the case of Example 1 and the area of high contrast isremarkably wide could be obtained. Also, where the field-of-view anglecharacteristics were measured with the scattering sheet removed, anormal picture image could be recognized in only a narrow field-of-viewangle as in the case of Example 1. Further, the brightness was almostthe same as that of prior art liquid crystal display elements.

What is claimed is:
 1. A reflection liquid crystal display comprising: afirst substrate; a second transparent substrate that is disposed forwardto the light-incident direction so that it is opposed to said firstsubstrate; a color filtering layer consisting of a liquid crystal layerplaced between said first substrate and second substrate, and acholesteric material layer secured between said first substrate and saidliquid crystal layer; an optical absorbing layer provided rearward ofsaid color filtering layer in the light-incident direction at said firstsubstrate side; a quarter-wavelength plate secured at said secondsubstrate side; and a polarization plate disposed further forward in thelight-incident direction than said quarter-wavelength plate.
 2. Areflection liquid crystal display comprising: a first substrate; asecond transparent substrate that is disposed forward to thelight-incident direction so that it is opposed to said first substrate;a color filtering layer consisting of a liquid crystal layer placedbetween said first substrate and second substrate, and a cholestericmaterial layer secured between said first substrate and said liquidcrystal layer; an optical absorbing layer provided rearward of saidcolor filtering layer in the light-incident direction at said firstsubstrate side; and a three-prime-color cholesteric material layerhaving inverted twisting of said cholesteric material layer, which isprovided at said second substrate side.
 3. The reflection liquid crystaldisplay as set forth in claim 1, further comprising a scattering layerfor scattering light forward to said polarization plate in thelight-incident direction.
 4. The reflection liquid crystal display asset forth in claim 2, further comprising a scattering layer forscattering light forward to said three-prime-color cholesteric materiallayer in the light-incident direction.
 5. The reflection liquid crystaldisplay as set forth in claim 3, wherein said scattering layer includes:two transparent electrodes opposed to each other; and a macromoleculardispersion liquid crystal layer placed between said transparentelectrode; wherein transmission and scattering of said macromoleculardispersion liquid crystal layer are switched by applying voltage to saidmacromolecular dispersion liquid crystal layer.
 6. The reflection liquidcrystal display as set forth in claim 4, wherein said scattering layerincludes: two transparent electrodes opposed to each other; and amacromolecular dispersion liquid crystal layer placed between saidtransparent electrode; wherein transmission and scattering of saidmacromolecular dispersion liquid crystal layer are switched by applyingvoltage to said macromolecular dispersion liquid crystal layer.
 7. Thereflection liquid crystal display as set forth in claim 1, furthercomprising: a plurality of scanning signal lines secured on the surfaceof said first substrate opposed to said second substrate; a plurality ofpicture signal lines disposed on these scanning signal lines in the formof a matrix; a plurality of thin-film transistors formed so as tocorrespond to the intersection of said scanning signal lines and saidpicture signal lines; at least one pixel that is constituted by an areasurrounded by said plurality of scanning signal lines and picture signallines; pixel electrodes that are connected to said thin-film transistorcorresponding to respective pixels and are formed rearward of saidliquid crystal layer in the incident direction of light; and a commonelectrode that is formed forward of said liquid crystal layer in theincident direction of light and applies a reference voltage to saidplurality of pixels.
 8. The reflection liquid crystal display as setforth in claim 2, further comprising: a plurality of scanning signallines secured on the surface of said first substrate opposed to saidsecond substrate; a plurality of picture signal lines disposed on thesescanning signal lines in the form of a matrix; a plurality of thin-filmtransistors formed so as to correspond to the intersection of saidscanning signal lines and said picture signal lines; at least one pixelthat is constituted by an area surrounded by said plurality of scanningsignal lines and picture signal lines; pixel electrodes that areconnected to said thin-film transistor corresponding to respectivepixels and are formed rearward of said liquid crystal layer in theincident direction of light; and a common electrode that is formedforward of said liquid crystal layer in the incident direction of lightand applies a reference voltage to said plurality of pixels.
 9. Thereflection liquid crystal display as set forth in claim 7, wherein atleast either one of said scanning electrode or a picture signalelectrode is provided with a part of said pixel electrode and ashielding electrode forward in the light-incident direction.
 10. Thereflection liquid crystal display as set forth in claim 8, wherein atleast either one of said scanning electrode or a picture signalelectrode is provided with a part of said pixel electrode and ashielding electrode forward in the light-incident direction.
 11. Thereflection liquid crystal display as set forth in claim 7, wherein saidpixel electrode is circular or equilaterally polygonal to have moresides than those of a triangle; a common electrode has a larger areathan that of said pixel electrode when being observed from upside, andis formed at a position where said common electrode covers the entiretyof said pixel electrode.
 12. The reflection liquid crystal display asset forth in claim 8, wherein said pixel electrode is circular orequilaterally polygonal to have more sides than those of a triangle; acommon electrode has a larger area than that of said pixel electrodewhen being observed from upside, and is formed at a position where saidcommon electrode covers the entirety of said pixel electrode.
 13. Thereflection liquid crystal display as set forth in claim 7, wherein saidpixel electrode is shaped so that a plurality of circles or equilateralpolygons which have more sides than those of a triangle are connected toeach other; and said common electrode has a larger area than that ofsaid pixel electrode when being observed from upside, and is formed at aposition where said common electrode covers the entirety of said pixelelectrode.
 14. The reflection liquid crystal display as set forth inclaim 8, wherein said pixel electrode is shaped so that a plurality ofcircles or equilateral polygons which have more sides than those of atriangle are connected to each other; and said common electrode has alarger area than that of said pixel electrode when being observed fromupside, and is formed at a position where said common electrode coversthe entirety of said pixel electrode.
 15. The reflection liquid crystaldisplay as set forth in claim 11, wherein said common electrode isformed on almost the entire surface of said second substrate.
 16. Thereflection liquid crystal display as set forth in claim 12, wherein saidcommon electrode is formed on almost the entire surface of said secondsubstrate.
 17. The reflection liquid crystal display as set forth inclaim 13, wherein said common electrode is formed on almost the entiresurface of said second substrate.
 18. The reflection liquid crystaldisplay as set forth in claim 14, wherein said common electrode isformed on almost the entire surface of said second substrate.
 19. Thereflection liquid crystal display as set forth in claim 11 wherein saidpixel electrode has cuts formed at equidistant positions on itscircumference or at respective corners of an equilateral polygon. 20.The reflection liquid crystal display as set forth in claim 12 whereinsaid pixel electrode has cuts formed at equidistant positions on itscircumference or at respective corners of an equilateral polygon. 21.The reflection liquid crystal display as set forth in claim 13 whereinsaid pixel electrode has cuts formed at equidistant positions on itscircumference or at respective corners of an equilateral polygon. 22.The reflection liquid crystal display as set forth in claim 14 whereinsaid pixel electrode has cuts formed at equidistant positions on itscircumference or at respective corners of an equilateral polygon. 23.The reflection liquid crystal display as set forth in claim 11, whereinsaid pixel electrode has projections formed at equidistant positions onits circumference or at respective corners of an equilateral polygon,which protrudes outward therefrom.
 24. The reflection liquid crystaldisplay as set forth in claim 12, wherein said pixel electrode hasprojections formed at equidistant positions on its circumference or atrespective corners of an equilateral polygon, which protrudes outwardtherefrom.
 25. The reflection liquid crystal display as set forth inclaim 13, wherein said pixel electrode has projections formed atequidistant positions on its circumference or at respective corners ofan equilateral polygon, which protrudes outward therefrom.
 26. Thereflection liquid crystal display as set forth in claim 14, wherein saidpixel electrode has projections formed at equidistant positions on itscircumference or at respective corners of an equilateral polygon, whichprotrudes outward therefrom.
 27. The reflection liquid crystal displayas set forth in claim 7, wherein a recess is formed at a part of saidpixel electrode.
 28. The reflection liquid crystal display as set forthin claim 8, wherein a recess is formed at a part of said pixelelectrode.
 29. The reflection liquid crystal display as set forth inclaim 1, wherein said liquid crystal layer includes a macromolecularorganic compound.
 30. The reflection liquid crystal display as set forthin claim 2, wherein said liquid crystal layer includes a macromolecularorganic compound.
 31. The reflection liquid crystal display as set forthin claim 1, wherein said liquid crystal layer has negative dielectricanisotropy in liquid crystal, and liquid crystal molecules are orientedin a direction orthogonal to said first and second substrates when novoltage is applied.
 32. The reflection liquid crystal display as setforth in claim 2, wherein said liquid crystal layer has negativedielectric anisotropy in liquid crystal, and liquid crystal moleculesare oriented in a direction orthogonal to said first and secondsubstrates when no voltage is applied.
 33. The reflection liquid crystaldisplay as set forth in claim 31, wherein said liquid crystal layer isgiven a pre-tilt angle in advance in a direction along which the liquidcrystal molecules are shifted down when voltage is applied.
 34. Thereflection liquid crystal display as set forth in claim 32, wherein saidliquid crystal layer is given a pre-tilt angle in advance in a directionalong which the liquid crystal molecules are shifted down when voltageis applied.
 35. The reflection liquid crystal display as set forth inclaim 1, wherein said liquid crystal layer has positive dielectricanisotropy in liquid crystal and has a twisted nematic structure when novoltage is applied.
 36. The reflection liquid crystal display as setforth in claim 2, wherein said liquid crystal layer has positivedielectric anisotropy in liquid crystal and has a twisted nematicstructure when no voltage is applied.
 37. The reflection liquid crystaldisplay as set forth in claim 35, wherein said liquid crystal layer inrespective pixels has two types of minute areas whose rise directions ofliquid crystal molecules are different from each other.
 38. Thereflection liquid crystal display as set forth in claim 36, wherein saidliquid crystal layer in respective pixels has two types of minute areaswhose rise directions of liquid crystal molecules are different fromeach other.
 39. The reflection liquid crystal display as set forth inclaim 35, wherein said liquid crystal layer in respective pixels has twotypes of minute areas whose twisting directions of liquid crystalmolecules are different from each other.
 40. The reflection liquidcrystal display as set forth in claim 36, wherein said liquid crystallayer in respective pixels has two types of minute areas whose twistingdirections of liquid crystal molecules are different from each other.41. The reflection liquid crystal display as set forth in claim 35,wherein said liquid crystal layer in respective pixels has four types ofminute areas whose twisting directions and rise directions of liquidcrystal molecules are different from each other.
 42. The reflectionliquid crystal display as set forth in claim 36, wherein said liquidcrystal layer in respective pixels has four types of minute areas whosetwisting directions and rise directions of liquid crystal molecules aredifferent from each other.
 43. The reflection liquid crystal display asset forth in claim 35, wherein the pre-tilt angle of liquid crystalmolecules at the boundary phase between said first substrate and secondsubstrate is 1 degree or less.
 44. The reflection liquid crystal displayas set forth in claim 36, wherein the pre-tilt angle of liquid crystalmolecules at the boundary phase between said first substrate and secondsubstrate is 1 degree or less.
 45. The reflection liquid crystal displayas set forth in claim 1, wherein said liquid crystal layer has positivedielectric anisotropy in liquid crystal, and has a homogenous structurewhen no voltage is applied.
 46. The reflection liquid crystal display asset forth in claim 2, wherein said liquid crystal layer has positivedielectric anisotropy in liquid crystal, and has a homogenous structurewhen no voltage is applied.
 47. The reflection liquid crystal display asset forth in claim 45, wherein said liquid crystal layer in respectivepixels has two types of minute areas whose rise directions of liquidcrystal molecules are different from each other.
 48. The reflectionliquid crystal display as set forth in claim 46, wherein said liquidcrystal layer in respective pixels has two types of minute areas whoserise directions of liquid crystal molecules are different from eachother.
 49. The reflection liquid crystal display as set forth in claim47, wherein the pre-tilt angle of liquid crystal molecules at theboundary phase between said first substrate and second substrate is 1degree or less.
 50. The reflection liquid crystal display as set forthin claim 48, wherein the pre-tilt angle of liquid crystal molecules atthe boundary phase between said first substrate and second substrate is1 degree or less.
 51. A method for producing a reflection liquid crystaldisplay, comprising the steps of: forming a thin-film transistor on afirst substrate; forming an optical absorbing layer on said firstsubstrate; forming a color filtering layer consisting of a cholestericmaterial layer on said optical absorbing layer; forming a pixelelectrode on said color filtering layer and connecting the same to saidthin-film transistor; forming a common electrode on a second substrate;making said pixel electrode of said first substrate opposite to saidcommon electrode of said second substrate, and forming a liquid crystallayer including a macromolecular organic compound between said firstsubstrate and second substrate; forming a quarter-wavelength plate onsaid second substrate; and forming a polarization plate on saidquarter-wavelength plate; wherein the step of forming said liquidcrystal layer further including the steps of: pouring liquid crystalincluding monomer or oligomer between said first substrate and saidsecond substrate; and making said monomer or oligomer macromolecular inliquid crystal.
 52. The method for producing a reflection liquid crystaldisplay as set forth in claim 51, further comprising the step of forminga pre-tilt angle at liquid crystal molecules of said liquid crystallayer by irradiation of light after the step of forming said liquidcrystal layer.
 53. The method for producing a reflection liquid crystaldisplay as set forth in claim 52, wherein said irradiation of light isdiagonally carried out with at least any one of said first substrate andsecond substrate.
 54. The method for producing a reflection liquidcrystal display as set forth in claim 52, wherein said irradiation oflight is diagonally carried out with polarized light for said first andsecond substrates.
 55. The method for producing a reflection liquidcrystal display as set forth in claim 52, wherein said irradiation oflight is carried out with polarized light for said first and secondsubstrates from the perpendicular direction.
 56. A method for driving areflection liquid crystal display defined in claim 1, wherein saiddisplay is dot-invertedly driven by inverting the polarities (positiveand negative) of voltage applied onto a liquid crystal layer of pixelsadjacent to each other.
 57. A method for driving a reflection liquidcrystal display defined in claim 2, wherein said display isdot-invertedly driven by inverting the polarities (positive andnegative) of voltage applied onto a liquid crystal layer of pixelsadjacent to each other.
 58. A method for driving a reflection liquidcrystal display defined in claim 1, wherein pixels are displayed to beblack by changing voltage applied onto a liquid crystal layer before oneframe is finished.
 59. A method for driving a reflection liquid crystaldisplay defined in claim 2, wherein pixels are displayed to be black bychanging voltage applied onto a liquid crystal layer before one frame isfinished.